[Causal association between immune cells and sepsis: a based on Mendelian randomization method study].

OBJECTIVE: To investigate the causal association between immune cell and different types of sepsis by using Mendelian randomization (MR) method, and to find the immune cell phenotypes causally associated with sepsis. METHODS: Summary data for various circulating immune cell phenotypes were obtained from the GWAS catalog (GCST90001391-GCST90002121). Sepsis data were sourced from the UK Biobank database. Single nucleotide polymorphisms (SNP) were used as instrumental variables. The correlation threshold of P < 5×10-6 was used to identify the strongly correlated instrumental variables, and the code was used to remove the linkage disequilibrium and the instrumental variables with F-value < 10. Inverse variance weighting (IVW) was used as the main research method to evaluate the stability and reliability of the results, including Cochran's Q test, MR-Egger regression and Leave one out. Reverse MR analysis was performed based on the immunophenotypic results of the removal of horizontal pleiotropy, and the immune cell phenotype with one-way causal association was obtained. Odds ratio (OR) and 95% confidence interval (95%CI) were used to represent the effect value of the results. RESULTS: CD16 on CD14-CD16+; monocyte had horizontal pleiotropy in sepsis (OR = 0.965 4, 95%CI was 0.933 5-0.998 3, P = 0.039 6). There were five immunophenotypes that had reverse causal associations with the types associated with sepsis. After excluding immune cell phenotypes with horizontal pleiotropy and reverse causation, a total of 42 immune cell phenotypes with sepsis, 36 immune cell phenotypes with sepsis (28-day death in critical care), 32 immune cell phenotypes with sepsis (critical care), 44 immune cell phenotypes with sepsis (28-day death), and 30 immune cell phenotypes had potential causal associations with sepsis (under 75 years old). After false discovery rate (FDR) correction, the correlations between BAFF-R on IgD- CD38br and sepsis (28-day death) were negative and strong (OR = 0.737 8, 95%CI was 0.635 9-0.856 0, P = 6.05×10-5, PFDR = 0.044 2). CONCLUSIONS: A variety of immune cell phenotypes may have a protective effect on sepsis, especially BAFF-R on IgD- CD38br expression is negatively correlated with sepsis (28-day death), which provides a new idea for immune modulation therapy in sepsis.

Ultra-low-dose rituximab is effective for the treatment of patients with minimal change disease - A retrospective study.

BACKGROUND PURPOSE: Rituximab (RTX),an anti-CD20 monoclonal antibody can effectively treat minimal change disease (MCD),with low toxicity and a reduced steroid dosage. The optimal dosage of RTX for treating MCD remains unclear. This study aimed to investigate the efficacy of an ultra-low-dose regimen of RTX (100 mg per week for 4 weeks) for treating MCD. METHODS: We retrospectively analyzed clinical data from 31 patients with MCD who received RTX. Seventeen patients received ultra-low-dose RTX (ULD-RTX) therapy, and 14 patients received standard-dose RTX (SD-RTX) therapy (500 mg weekly for 4 weeks). All patients were followed up for at least 6 months. RESULTS: Both groups showed significant increases in the serum albumin levels and notable decreases in the urinary protein levels in the 1st and 6th months after RTX therapy. There were no significant differences in the plasma albumin or urinary protein levels between the groups (p > 0.05). B-cell depletion was observed in all patients after 1 month of RTX administration. At 6 months after RTX treatment, the remission rate was 93% in the SD-RTX group and 88% in the ULD-RTX group (p > 0.05). The ULD-RTX therapy incurred lower costs than did the SD-RTX therapy. One patient in the SD-RTX group developed community-acquired pneumonia. CONCLUSION: Ultra-low-dose RTX is effective at inducing remission in patients with MCD at a lower cost.

Establishment and Characterization of a New Cell Line from Enzootic Nasal Adenocarcinoma in Goats: ENA-1.

Enzootic nasal adenocarcinoma (ENA) is a contagious tumor disease of goats and sheep, which is caused by enzootic nasal tumor virus (ENTV). To better understand the pathogenesis of ENA, this study aimed to establish a goat ENA cell line (ENA-1). The cells have been characterized with regard to morphology, growth rate, ultrastructural features, chromosome number, expression of CK7 and CK18, tumorigenicity, species, and mycoplasma contamination. ENA-1 had an epithelioid cell morphology with an unstable chromosome number under a light microscope. Under an electron microscope, the cell nuclear heterogeneity was not obvious, and there were more intermediate filaments and a small number of immature retrovirus-like particles in the cytoplasm. ENA-1 had strong proliferative potential, and the cell multiplication time was about 36 h, which could make BALB/c nude mice develop tumors. CK7 and CK18 were expressed in the cytoplasm of primary goat tumors, in transplanted tumors from nude mice, and un ENA-1 cells with the same intensity. PCR revealed that ENA-1 continuously carried ENTV-2 up to the 17th generation with no germline contamination or mycoplasma contamination. In conclusion, using a serum-containing culture system, ENA-1 cells were successfully isolated, cultured, and purified from goat tumor tissues. The isolated ENA-1 cells retained robust proliferation potential and maintained their phenotype, indicating the potential application of the ENA-1 cell line as an in vitro model of ENA.

Qilong capsule prevents myocardial ischemia/reperfusion injury by inhibiting platelet activation via the platelet CD36 signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Qilong capsule (QC) is developed from the traditional Chinese medicine formula Buyang Huanwu Decoction, which has been clinically used to invigorate Qi and promote blood circulation to eliminate blood stasis. Myocardial ischemia‒reperfusion injury (MIRI) can be attributed to Qi deficiency and blood stasis. However, the effects of QC on MIRI remain unclear. AIM OF THE STUDY: This study aimed to investigate the protective effect and possible mechanism of QC on platelet function in MIRI rats. MATERIALS AND METHODS: The left anterior descending artery of adult Sprague‒Dawley rats was ligated for 30 min and then reperfused for 120 min with or without QC treatment. Then, the whole blood viscosity, plasma viscosity, coagulation, platelet adhesion rate, platelet aggregation, and platelet release factors were evaluated. Platelet CD36 and its downstream signaling pathway-related proteins were detected by western blotting. Furthermore, the active components of QC and the molecular mechanism by which QC regulates platelet function were assessed via molecular docking, platelet aggregation tests in vitro and BLI analysis. RESULTS: We found that QC significantly reduced the whole blood viscosity, plasma viscosity, platelet adhesion rate, and platelet aggregation induced by ADP or AA in rats with MIRI. The inhibition of platelet activation by QC was associated with reduced levels of ß-TG, PF-4, P-selectin and PAF. Mechanistically, QC effectively attenuated the expression of platelet CD36 and thus inhibited the activation of Src, ERK5, and p38. The active components of QC apparently suppressed platelet aggregation in vitro and regulated the CD36 signaling pathway. CONCLUSIONS: QC improves MIRI-induced hemorheological disorders, which might be partly attributed to the inhibition of platelet activation via CD36-mediated platelet signaling pathways.

Cytochrome P450 BsCYP99A44 and BsCYP704A177 Confer Metabolic Resistance to ALS Herbicides in Beckmannia syzigachne.

Beckmannia syzigachne is a noxious grassy weed that infests wheat fields in China. Previously, we identified that mesosulfuron-methyl resistance in a B. syzigachne population (R, SD04) was conferred by non-target resistance, such as cytochrome P450 mixed-function oxidases (P450s)-based metabolism. RNA sequencing and real-time PCR (qRT-PCR) were used to discover potential P450s-resistant-related genes. Five cytochrome P450s (CYP704A177, CYP96B84, CYP71D7, CYP93A1, and CYP99A44) were found to be highly expressed in R plants. In this study, CYP99A44 and CYP704A177 were cloned from B. syzigachne and transferred into Arabidopsis thaliana to test the sensitivity of Arabidopsis with and without P450s genes to mesosulfuron-methyl and other acetolactate synthase (ALS)-inhibiting herbicides. Transgenic Arabidopsis overexpressing CYP99A44 became resistant to the sulfonylurea herbicide mesosulfuron-methyl, but showed no resistance to pyroxsulam, imazethapyr, flucarbazone, and bispyribac-sodium. Notably, those overexpressing CYP704A177 showed resistance to pyroxsulam and bispyribac-sodium, but not to mesosulfuron-methyl, imazethapyr, and flucarbazone. These results indicated that B. syzigachne and transgenic Arabidopsis displayed different cross-resistance patterns to ALS-inhibiting herbicides. Subcellular localization revealed that CYP99A44 and CYP704A177 protein were located in the endoplasmic reticulum. Furthermore, these results clearly indicated that CYP99A44-mediated mesosulfuron-methyl resistance in B. syzigachne and CYP704A177 may be involved in B. syzigachne cross-resistance to pyroxsulam and bispyribac-sodium.

The Comparison of PCR Kits for the Detection of Erythrocytic Parasites on Filter Paper.

Dried blood spot (DBS) based PCR was considered an inexpensive and feasible method for detecting pathogens in the blood. The DBS carrier filter paper and PCR kits are crucial for accurate diagnosis. We evaluated 4 types of filter papers and 20 PCR kits for DBS samples. The PCR detecting Plasmodium results showed that the minimum detection limit of the 4 filter papers was 1 × 102 parasites/µL, and the positive rates of 20 PCR kits ranged from 0% to 100%. PCR results were satisfactory for detecting Plasmodium falciparum (P. falciparum) and Plasmodium. vivax (P. vivax) in archived DBS samples and Babesia gibsoni (B. gibsoni) in fresh pet DBS samples. Our results provided a useful reference for the detection of blood pathogens with DBS samples and direct PCR, especially for screening the cost-efficacy combination of filter paper and PCR kit in resource-limited areas.

EVALUATION OF THE INHIBITORY EFFECTS OF SIX NATURAL PRODUCT EXTRACTS AGAINST BABESIA GIBSONI IN VITRO AND IN VIVO.

New antibabesial drugs are required to fight resistant parasites, and plant-derived natural products are a robust source. Six kinds of natural product extracts derived from herbal medicines that are traditionally used for the treatment of malaria were selected to test the antibabesial effect on Babesia gibsoni in vitro and in vivo. Parasitized blood was collected from dogs infected with B. gibsoni to evaluate the inhibitory effect of verbenalin, catechin hydrate, dihydrolycorine, embelin, ursolic acid, agrimol B, and bruceine H in vitro. The expression levels of the 18S rRNA gene in all drug-treated groups were determined by relative quantification using a real-time PCR method. Significant inhibition of the in vitro growth of B. gibsoni was observed after treatment by those natural product extracts (200 nM concentration) (P < 0.05). Catechin hydrate showed the highest activity in vitro due to the lowest expression levels of the 18S rRNA gene. The IC50 value of catechin hydrate against B. gibsoni was 273 nM. In B. gibsoni infected dogs, intravenous administrations of catechin hydrate and diminazene aceturate showed significant (P < 0.05) inhibition of B. gibsoni growth at a dose of 11 mg/kg and 10 mg/kg, respectively, compared to the control group. The results of our study may suggest that catechin hydrate may be a promising alternative to treat canine babesiosis caused by B. gibsoni.

Dynamic Mitochondrial Proteome Under Polyamines Treatment in Cardiac Aging.

Age-related alteration of mitochondria causes impaired cardiac function, along with cellular and molecular changes. Polyamines can extend the life span in mice. However, whether polyamines can affect the dynamic mitochondrial proteome, thereby preventing age-related changes in cardiac function and cardiac aging, remains unclear. In this study, we found that spermine (Spm) and spermidine (Spd) injection for 6 weeks could prevent 24-month-old rats heart dysfunction, improve mitochondrial function, and downregulate apoptosis. Using iTRAQ tools, we identify 75 mitochondrial proteins of statistically significant alteration in aging hearts, which mainly participate in important mitochondrial physiological activity, such as metabolism, translation, transport, apoptosis, and oxidative phosphorylation. Moreover, four proteins of differential expression, pyruvate dehydrogenase kinase (PDK4), trifunctional enzyme subunit alpha (HADHA), nicotinamide nucleotide transhydrogenase (NNT), and Annexin6, which were significantly associated with heart aging, were validated by Western blotting. In vitro, we further demonstrated polyamines could retard cardiomyocytes aging through downregulating the expression of PDK4 and thereby inhibiting cell apoptosis. In summary, the distinct mitochondrial proteins identified in this study suggested some candidates involved in the anti-aging of the heart after polyamines treatment, and PDK4 may provide molecular clues for polyamines to inhibit apoptosis and thus retard aging-induced cardiac dysfunction.

Radiography, CT, and MRI Diagnosis of Enzootic Nasal Tumor in Goats Infected With Enzootic Nasal Tumor Virus.

The aim of this study was to describe radiography, computed tomography (CT), and magnetic resonance imaging (MRI) findings of enzootic nasal tumors in goats infected with enzootic nasal tumor viruses. Five of six goats with a mean age of 2 years, showed clinical signs of respiratory disease. Head radiographs showed increased density of the unilateral or bilateral nasal cavity in four goats, and a CT scan showed that the space-occupying lesion of the nasal cavity originated from the ethmoid bone and was enhanced homogeneously postcontrast in all goats. The nasal concha was destroyed and the paranasal sinus mucosa was thickened and filled with fluid in some goats. On MRI, the mass exhibited equal or slightly higher signal intensity on T2 weighted images, equal signal intensity on T1 weighted images, a high signal on fluid-attenuated inversion recovery images and heterogeneous enhancement postcontrast. After dissection, histopathological examination of the mass and virus genome detection of the nasal secretions confirmed that the intranasal mass was a low-grade adenocarcinoma and that the goats were infected with enzootic nasal tumor virus type 2. In conclusion, CT and MRI have high diagnostic values for enzootic nasal tumors because they match the postmortem findings and are more accurate than radiography.

Spermidine Alleviates Intrauterine Hypoxia-Induced Offspring Newborn Myocardial Mitochondrial Damage in Rats by Inhibiting Oxidative Stress and Regulating Mitochondrial Quality Control.

Background: Intrauterine hypoxia (IUH) increases the risk of cardiovascular diseases in offspring. As a reactive oxygen species (ROS) scavenger, polyamine spermidine (SPD) is essential for embryonic and fetal survival and growth. However, further studies on the SPD protection and mechanisms for IUH-induced heart damage in offspring are required. Objectives: This study aimed to investigate the preventive effects of prenatal SPD treatment on IUH-induced heart damage in newborn offspring rats and its underlying mitochondrial-related mechanism. Methods: The rat model of IUH was established by exposure to 10% O2 seven days before term. Meanwhile, for seven days, the pregnant rats were given SPD (5 mg.kg-1.d-1; ip). The one-day offspring rats were sacrificed to assess several parameters, including growth development, heart damage, cardiomyocytes proliferation, myocardial oxidative stress, cell apoptosis, and mitochondrial function, and have mitochondrial quality control (MQC), including mitophagy, mitochondrial biogenesis, and mitochondrial fusion/fission. In in vitro experiments, primary cardiomyocytes were subjected to hypoxia with or without SPD for 24 hours. Results: IUH decreased body weight, heart weight, cardiac Ki67 expression, the activity of SOD, and the CAT and adenosine 5'-triphosphate (ATP) levels and increased the BAX/BCL2 expression, and TUNEL-positive nuclei numbers. Furthermore, IUH also caused mitochondrial structure abnormality, dysfunction, and decreased mitophagy (decreased number of mitophagosomes), declined mitochondrial biogenesis (decreased expression of SIRT-1, PGC-1α, NRF-2, and TFAM), and led to fission/fusion imbalance (increased percentage of mitochondrial fragments, increased DRP1 expression, and decreased MFN2 expression) in the myocardium. Surprisingly, SPD treatment normalized the variations in the IUH-induced parameters. Furthermore, SPD also prevented hypoxia-induced ROS accumulation, mitochondrial membrane potential decay, and the mitophagy decrease in cardiomyocytes. Conclusion: Maternal SPD treatment caused IUH-induced heart damage in newborn offspring rats by improving the myocardial mitochondrial function via anti-oxidation and anti-apoptosis, and regulating MQC.

Impact of intrauterine hypoxia on adolescent and adult cognitive function in rat offspring: sexual differences and the effects of spermidine intervention.

Intrauterine hypoxia (IUH) affects the growth and development of offspring. It remains unclear that how long the impact of IUH on cognitive function lasts and whether sexual differences exist. Spermidine (SPD) has shown to improve cognition, but its effect on the cognitive function of IUH offspring remains unknown. In the present study we investigated the influence of IUH on body weight and neurological, motor and cognitive function and the expression of APP, BACE1 and Tau5 proteins in brain tissues in 2- and 4-month-old IUH rat offspring, as well as the effects of SPD intervention on these parameters. IUH rat model was established by treating pregnant rats with intermittent hypoxia on gestational days 15-21, meanwhile pregnant rats were administered SPD (5 mg·kg-1·d-1;ip) for 7 days. Neurological deficits were assessed in the Longa scoring test; motor and cognitive functions were evaluated in coat hanger test and active avoidance test, respectively. We found that IUH decreased the body weight of rats in both sexes but merely impaired motor and cognitive function in female rats without changing neurological function in the rat offspring of either sex at 2 months of age. For 4-month-old offspring, IUH decreased body weight in males and impaired neurological function and increased cognitive function in both sexes. IUH did not affect APP, BACE1 or Tau5 protein expression in either the hippocampus or cortex of all offspring; however, it increased the cortical Tau5 level in 2-month-old female offspring. Surprisingly, SPD intervention prevented weight loss. SPD intervention reversed the motor and cognitive decline caused by IUH in 2-month-old female rat offspring. Taken together, IUH-induced cognitive decline in rat offspring is sex-dependent during puberty and can be recovered in adult rats. SPD intervention improves IUH-induced cognitive and neural function decline.

Identification and expression of main genes involved in non-target site resistance mechanisms to fenoxaprop-p-ethyl in Beckmannia syzigachne.

BACKGROUND: Non-target-site resistance (NTSR) to herbicides is a serious threat to global agriculture. Although metabolic resistance is the dominant mechanism of NTSR, the molecular mechanisms are not yet well-characterized. This study aimed to uncover the likely metabolism-related genes in Beckmannia syzigachne (American sloughgrass) resistant to fenoxaprop-p-ethyl. RESULTS: Ultra-performance liquid chromatography - tandem mass spectrometry experiments showed that the resistant American sloughgrass biotype (R, SD-04-SS) showed enhanced degradation of this herbicide compared to the susceptible biotype (S, SD-12). R and S biotype were harvested at 24 h after fenoxaprop-p-ethyl treatment to conduct RNA sequencing (RNA-Seq) analysis to investigate the likely fenoxaprop-p-ethyl metabolic genes. The RNA-Seq libraries yield 417 969 980 clean reads. The de novo assembly generated 115 112 unigenes, of which 57 906 unigenes were annotated. Finally, we identified 273 cytochrome P450s, 178 oxidases, 47 glutathione S-transferases (GSTs), 166 glucosyltransferases (GTs) and 180 ABC transporter genes to determine the likely fenoxaprop-p-ethyl metabolism-related genes in R biotype. Twelve overlapping up-regulated genes in the R biotype (fenoxaprop-p-ethyl-treated R/non-treated R, fenoxaprop-p-ethyl-treated R/fenoxaprop-p-ethyl-treated S) were identified by RNA-Seq and the results were validated using qRT-PCR. Ten were identified as fenoxaprop-p-ethyl metabolism-related genes, including three P450s (homologous to CYP71D7, CYP99A2 and CYP71D10), one GST (homologous to GSTF1), two GTs (homologous to UGT90A1 and UGT83A1) and four oxidase genes. CONCLUSION: This work demonstrates that the NTSR mechanism by means of enhanced detoxification of fenoxaprop-p-ethyl in American sloughgrass is very likely driven by herbicide metabolism related genes. The RNA-Seq data presented here provide a valuable resource for understanding the molecular mechanism of NTSR in American sloughgrass. © 2020 Society of Chemical Industry.

Spermidine alleviates cardiac aging by improving mitochondrial biogenesis and function.

Polyamines have been shown to delay cellular and organismal aging and to provide cardiovascular protection in humans. Because age-related cardiovascular dysfunction is often accompanied by impaired mitochondrial biogenesis and function, we explored the ability of spermidine (SPD), a major mammalian polyamine, to attenuate cardiac aging through activation of mitochondrial biogenesis. Cardiac polyamine levels were reduced in aged (24-month-old) rats. Six-week SPD supplementation restored cardiac polyamine content, preserved myocardial ultrastructure, and inhibited mitochondrial dysfunction. Immunoblotting showed that ornithine decarboxylase (ODC) and SPD/spermine N1-acetyltransferase (SSAT) were downregulated and upregulated, respectively, in the myocardium of older rats. These changes were paralleled by age-dependent downregulation of components of the sirtuin-1/peroxisome proliferator-activated receptor gamma coactivator alpha (SIRT1/PGC-1α) signaling pathway, an important regulator of mitochondrial biogenesis. SPD administration increased SIRT1, PGC-1α, nuclear respiratory factors 1 and 2 (NRF1, NRF2), and mitochondrial transcription factor A (TFAM) expression; decreased ROS production; and improved OXPHOS performance in senescent (H2O2-treated) cardiomyocytes. Inhibition of polyamine biosynthesis or SIRT1 activity abolished these effects. PGC-1α knockdown experiments confirmed that SPD activated mitochondrial biogenesis through SIRT1-mediated deacetylation of PGC-1α. These data provide new insight into the antiaging effects of SPD, and suggest potential applicability to protect against deterioration of cardiac function with aging.

Corrigendum to "Spermidine Prevents Heart Injury in Neonatal Rats Exposed to Intrauterine Hypoxia by Inhibiting Oxidative Stress and Mitochondrial Fragmentation".

[This corrects the article DOI: 10.1155/2019/5406468.].

Molecular basis for the resistance of American sloughgrass to aryloxyphenoxypropionic acid pesticides and its environmental relevance: A combined experimental and computational study.

Organic pesticides are one of the main environmental pollutants, and how to reduce their environmental risks is an important issue. In this contribution, we disclose the molecular basis for the resistance of American sloughgrass to aryloxyphenoxypropionic acid pesticides using site-directed mutagenesis and molecular modeling and then construct an effective screening model. The results indicated that the target-site mutation (Trp-1999-Leu) in acetyl-coenzyme A carboxylase (ACCase) can affect the effectiveness of the pesticides (clodinafop, fenoxaprop, cyhalofop, and metamifop), and the plant resistance to fenoxaprop, clodinafop, cyhalofop, and metamifop was found to be 564, 19.5, 10, and 0.19 times, respectively. The established computational models (i.e. wild-type/mutant ACCase models) could be used for rational screening and evaluation of the resistance to pesticides. The resistance induced by target gene mutation can markedly reduce the bioreactivity of the ACCase-clodinafop/fenoxaprop adducts, and the magnitudes are 10 and 102, respectively. Such event will seriously aggravate environmental pollution. However, the biological issue has no distinct effect on cyhalofop (RI＝10), and meanwhile it may markedly increase the bioefficacy of metamifop (RI＝0.19). We could selectively adopt the two chemicals so as to decrease the residual pesticides in the environment. Significantly, research findings from the computational screening models were found to be negatively correlated with the resistance level derived from the bioassay testing, suggesting that the screening models can be used to guide the usage of pesticides. Obviously, this story may shed novel insight on the reduction of environmental risks of pesticides and other organic pollutants.

Cross-resistance pattern to ACCase-inhibiting herbicides in a novel Trp1999Leu mutation American sloughgrass (Beckmannia syzigachne) population.

The plastid acetyl coenzyme carboxylase (ACCase) Trp1999Leu mutation was identified in a Beckmannia syzigachne population resistant to fenoxaprop-p-ethyl. The pattern of cross-resistance for the Trp1999Leu mutation is still ambiguous. In this paper, mutant homozygote (1999Leu/Leu, RR) and wild type (1999Trp/Trp, SS) B. syzigachne plants with the same genetic background were purified from the JS-26 population using the dCAPS method. The activity of ACCase in RR and SS was determined. Then, the cross-resistance pattern to ACCase inhibiting herbicides of the Trp1999Leu mutation was determined using the whole-plant method. ACCase activity showed that the Trp1999Leu mutation decreased ACCase sensitivity to fenoxaprop-p-ethyl by 2.73-fold. A dose-response experiment indicated that the Trp1999Leu mutation conferred high resistance to quizalofop-p-ethyl (20.29-fold), metamifop (12.22-fold) and pinoxaden (18.60-fold), moderate resistance to fenoxaprop-p-ethyl (8.20-fold) and sethoxydim (6.38-fold), low resistance to cyhalofop-butyl (2.73-fold) and no resistance to clodinafop-propargyl (1.42 fold) and clethodim (1.59-fold). This is the first report of the role of Trp1999Leu in fenoxaprop-p-ethyl resistance and of the patterns of cross-resistance to ACCase-inhibiting herbicides in B. syzigachne.

Spermidine Prevents Heart Injury in Neonatal Rats Exposed to Intrauterine Hypoxia by Inhibiting Oxidative Stress and Mitochondrial Fragmentation.

Intrauterine hypoxia (IUH) is a common intrauterine dysplasia that can cause programming of the offspring cardiovascular system. In this study, we hypothesized that placental treatment with spermidine (SPD) can prevent heart injury in neonatal offspring exposed to IUH. Pregnant rats were exposed to 21% O2 or 10% O2 (hypoxia) for 7 days prior to term or were exposed to hypoxia and intraperitoneally administered SPD or SPD+difluromethylornithine (DFMO) on gestational days 15-21. Seven-day-old offspring were then sacrificed to assess several parameters. Our results demonstrated that IUH led to decreased myocardial ornithine decarboxylase (ODC) and increased spermidine/spermine N1-acetyltransferase (SSAT) expression in the offspring. IUH also resulted in decreased offspring body weight, heart weight, cardiomyocyte proliferation, and antioxidant capacity and increased cardiomyocyte apoptosis and fibrosis. Furthermore, IUH caused mitochondrial structure abnormality, dysfunction, and decreased biogenesis and led to a fission/fusion imbalance in offspring hearts. In vitro, hypoxia induced mitochondrial ROS accumulation, decreased membrane potential, and increased fragmentation. Notably, all hypoxia-induced changes analyzed in this study were prevented by SPD. Thus, in utero SPD treatment is a potential strategy for preventing IUH-induced neonatal cardiac injury.

Seismic collapse assessment of bridge piers constructed with steel fibers reinforced concrete.

Steel fiber is one of the most widely used reinforcements to improve the performance of concrete members. However, few studies have been proposed to study the seismic performance of bridge piers constructed with steel fiber reinforced concrete. This paper presents the collapse vulnerability assessment of typical single bridge piers constructed with steel fibers. Fiber element models of RC bridge piers with and without steel fibers are firstly built by selecting suitable cyclic constitutive laws of steel fiber reinforced concrete, and then calibrated using the experimental results. The seismic capacity and inelastic demand of RC piers with steel fibers are quantified using both nonlinear static pushover analyses and nonlinear incremental dynamic analyses (IDA). In order to conduct the IDA, a suite of 20 earthquake ground motions are selected and scaled to different levels of peak ground acceleration (PGA). Collapse fragility curves are then generated using the maximum drift ratio of piers as the engineering demand parameter (EDP). In order to investigate the impact of various parameters on the collapse fragility curves, six parameters are considered in the parametric study: peak compressive strength of concrete, yield strength of steel, longitudinal reinforcement ratio, axial load ratio, transverse hoops ratio and steel fiber content. It was observed that the concrete strength, longitudinal reinforcement ratio and steel fiber content could significantly affect the collapse fragility curve of the bridge piers with steel fibers.

New evidence for primordial action site of Fluazifop-P-butyl on Acanthospermum hispidum seedlings: From the effects on chlorophyll fluorescence characteristics and histological observation.

Acanthospermum hispidum DC, an Asteraceae weed species, was very susceptible to fluazifop-P-butyl, but tolerant to other aryloxyphenoxypropionate herbicides, such as haloxyfop-P-methyl. However, other Asteraceae weeds including Bidens pilosa were all tolerant to fluazifop-P-butyl. Membrane lipid peroxidation by increasing the levels of reactive oxygen species (ROS) was proposed as an action mechanism of fluazifop-P-butyl in A. hispidum. To further clarify the primordial action site of fluazifop-P-butyl in this species, the effects on chlorophyll fluorescence characteristics and cytohistology of apical meristems were studied. Chlorophyll fluorescence characteristics (CFC) in sensitive A. hispidum seedlings were markedly affected by 10µM fluazifop-P-butyl, with the dark fluorescence yield (Fo), maximal fluorescence yield (Fm), maximal PS II quantum yield (Fv/Fm), effective photosystem II (PS II) quantum yield [Y(II)], and quantum yield of regulated energy dissipation [Y(NPQ)] declining, quantum yield of nonregulated energy dissipation [Y(NO)] rising, but these measures were not affected in Bidens pilosa. The effects of fluazifop-P-butyl on chlorophyll fluorescence properties were observed on the growing point before the mature leaves by about 4-6h. Haloxyfop-P-methyl, a control herbicide, had no effects on CFC of either A. hispidum or B. pilosa. In addition, damage to apical meristem cells of A. hispidum was observed at 6 HAT prior to changes in chlorophyll fluorescence parameters suggesting that the primary action site of fluazifop-P-butyl in this species is in the apical meristem and the effects on CFC may be the results of secondary action.

Fluazifop-P-butyl induced ROS generation with IAA (indole-3-acetic acid) oxidation in Acanthospermum hispidum D.C.

Acanthospermum hispidum D.C. was particularly susceptible to fluazifop-P-butyl, an aryloxyphenoxypropionate herbicide, and the primary action site for the herbicide was shoot apical meristem, which is also the main site of indole-3-acetic acid (IAA) biosynthesis and action. Membrane lipid peroxidation caused by increasing levels of reactive oxygen species (ROS) was considered as an action mechanism of fluazifop-P-butyl in A. hispidum. To further clarify the ROS inducing mechanism of fluazifop-P-butyl in the plant, the interactions between fluazifop-P-butyl and auxin compounds IAA or 2,4-dichlorophenoxyacetic acid (2,4-D) were studied. Haloxyfop-P-methyl, an AOPP herbicide which is inactive on A. hispidum, was used for comparison. The results showed that the growth inhibition and malondialdehyde or H2O2 increases induced by fluazifop-P-butyl on A. hispidum were reversed by IAA or 2,4-D. The IAA content was decreased but the contents of three IAA oxidation metabolites, indole-3-methanol, indole-3-aldehyde and indole-3-carboxylic acid were increased by fluazifop-P-butyl in A. hispidum, but not by haloxyfop-P-methyl. The growth of A. hispidum was not inhibited by three IAA oxidative compounds. Moreover, the activities of IAA oxidase and peroxidase were increased by fluazifop-P-butyl but not by haloxyfop-P-methyl, and the increase was reversed by IAA or 2,4-D. We suggest that there is an antagonistic effect between fluazifop-P-butyl and IAA or 2,4-D, and the IAA oxidation may be involved in the action mechanism of fluazifop-P-butyl in A. hispidum.