SreC-dependent adaption to host iron environments regulates the transition of trophic stages and developmental processes of Curvularia lunata.

Plant pathogens are challenged by host-derived iron starvation or excess during infection, but the mechanism of plant pathogens rapidly adapting to the dynamic host iron environments to assimilate iron for invasion and colonization remains largely unexplored. Here, we found that the GATA transcription factor SreC in Curvularia lunata is required for virulence and adaption to the host iron excess environment. SreC directly binds to the ATGWGATAW element in an iron-dependent manner to regulate the switch between different iron assimilation pathways, conferring adaption to host iron environments in different trophic stages of C. lunata. SreC also regulates the transition of trophic stages and developmental processes in C. lunata. SreC-dependent adaption to host iron environments is essential to the infectious growth and survival of C. lunata. We also demonstrate that CgSreA (a SreC orthologue) plays a similar role in Colletotrichum graminicola. We conclude that Sre mediates adaption to the host iron environment during infection, and the function is conserved in hemibiotrophic fungi.

Highly efficient gene knockout system in the maize pathogen Colletotrichum graminicola using Agrobacterium tumefaciens-mediated transformation (ATMT).

Colletotrichum graminicola, a hemibiotrophic pathogenic fungus, is the causal agent of anthracnose of maize, which causes significant yield losses worldwide, especially in warm and humid maize production regions. An efficient targeted genes knockout protocol is crucial to explore molecular mechanisms of fungal virulence to the host. In this study, we established a gene knockout transformation system by employing Agrobacterium tumefaciens-mediated transformation to knockout genes in M 1.001 strain of C. graminicola. The conidia germination status, induction medium type, and ratio of Agrobacterium cell and conidia suspension were optimized for the knockout of CgBRN1(OR352905), a gene relating to the fungal melanin biosynthesis pathway. Additionally, CgPKS18 (OR352906) and CgCDC25 (OR352903) were knocked out to test the applicability of the gene knockout transformation system. In this established system, transformation efficiency was 176 transformants per 1 × 105 conidia and the homologous recombination efficiency was 53.3 to 75%. Furthermore, disease index, lesion number and lesion size caused by the three above-mentioned mutant strains were found to be reduced significantly compared to the wild-type strain, which indicated reduction in fungal virulence due to the lack of those genes.

A secreted phospholipase A2 (BmsPLA2 ) regulates melanization of immunity through BmDDC in the silkworm Bombyx mori.

Insect immune-associated phospholipase A2 (PLA2 ) is an important target of pathogen invasion. Melanization, an effective defense response, has significant correlations with other immune responses to coordinate immune attack against invaders. However, the effect of PLA2 on melanization has not yet been reported in insects or other arthropods. In this work, we cloned a PLA2 gene (BmsPLA2 ), and its protein had characteristic features of secreted PLA2 (sPLA2 ). After injection of bacteria, BmsPLA2 expression and sPLA2 activity in hemolymph significantly increased. BmsPLA2 fluorescence was transferred from the cytoplasm to the cell membranes of circulating hemocytes. These results indicated that BmsPLA2 was related to hemolymph immunity in silkworms. Interestingly, reducing BmsPLA2 by RNA interference decreased melanosis (melanistic hemocytes) levels in vivo and in vitro, while BmsPLA2 overexpression had the opposite effect. The larval survival and melanization rate in the hemocoel both slowed depending on the PLA2 inhibitor dosage. These results demonstrated that BmsPLA2 plays a role in melanization during the immune process of silkworms. Surprisingly, the level of BmDDC matched the degree of melanization in various observations. BmDDC expression showed a significant increase, with the peak occurring later than that of BmsPLA2 after injection of bacteria, implying that BmsPLA2 was activated prior to BmDDC. Moreover, the alteration of BmsPLA2 by RNA interference or overexpression led to altered BmDDC levels. These results suggested that BmsPLA2 regulates the melanization response in silkworms through BmDDC. Our study proposes a new regulatory mechanism of the melanization response and new directions for understanding the complex immune networks of insects.

Detection of ochratoxin A by fluorescence sensing based on mesoporous materials.

We developed a new ochratoxin A (OTA) aptamer biosensor to promptly detect OTA in food. Mesoporous silica nanoparticles were used as carriers, and aptamers were used as recognition probes and gating molecules. The fluorescent dye rhodamine 6G was loaded into mesoporous silica, and through electrostatic contact, the OTA aptamer was adsorbed on amino-modified mesoporous silica. The fluorescent dye released from the mesopore in the presence of OTA because of the conformational change induced in the aptamer by the target. The amount of ochratoxin was determined by measuring the fluorescence intensity. Our findings revealed a positive relationship between the fluorescence intensity and OTA concentration, with a limit of detection of 0.28 ng mL-1, and the detection range was 0.05-200 ng mL-1. The recovery rate was 80.7%-110.8% in real samples. The proposed approach is suitable for the quantification of other toxins.

Microwave-assisted synthesis of defective Ca1-xAgxTi1-yCoyO3 with high photoelectrocatalytic activity for organic pollutant removal from water.

CaTiO3 is considered to be one of the most promising catalysts for the degradation of organic pollutants, but its application is limited by the wide band gap and low catalytic activity. Element doping is an effective strategy to solve these problems. Herein, a novel CaTiO3 co-doped with Ag and Co (Ca1-xAgxTi1-yCoyO3) was synthesized by combining co-precipitation and the microwave hydrothermal method for the first time. The crystal structure, microstructure and light absorption of the material were systematically investigated. The results showed that Ca1-xAgxTi1-yCoyO3 had higher light absorption than pure CaTiO3, and the band gap was reduced to 2.78 eV. First-principles calculations indicated that Ag-Ca and Co-Ti tended to form donor-acceptor defect pairs in the doping process. These defect states not only enhanced the adsorption properties, but also could be used as carrier traps to optimize the dielectric properties of CaTiO3. In the photoelectrocatalytic system, with 0.01 g of catalyst, 98% of methylene blue in 100 mL solution (10 mg L-1) was degraded in 150 min. In addition, Ca1-xAgxTi1-yCoyO3 showed strong stability and excellent recyclability. The double ion co-doping technology will provide an effective strategy for improving the catalytic activity of traditional wide-band gap semiconductors.

Effect of Composite Nanoparticle CeO2 on Myocardial Ischemic Re-Infusion of Cardio Myocyte Apoptosis in Mouse.

The myocardial I/R damage is very complicated. Apoptosis is considered to its a critical mechanism. During the cardiac muscle I/R process, oxygen-free radicals play a pivotal role. Arrhythmias, as well as enlargement of the area of myocardial infarction after cardiac muscle I/R process, are caused by adequate blast generated O2- ion free radicals. During the ischemia-reperfusion process, a large amount of O2- ion free radicals destroyed the cell structure, and it undergoes lipid peroxidation with unsaturated fatty acids that contain a large number of phospholipids in the cell membrane, causing membrane proteins such as ion channels and enzymes on the cell membrane. The activity of cell is reduced, which affects the function of cell membrane and organelle membrane, destroys its integrity and reduces fluidity.We observed the effects of cerium dioxide nanoparticles on glutathione peroxidase as well as superoxide dismutase, also propionate in myocardial tissue of I/R injury in the mouse. Its effects of malondialdehyde and apoptosis were explored to see its protective effect and to provide more preventive measures for ischemia-reperfusion injury.

Binding of aldehydes to myofibrillar proteins as affected by two-step heat treatments.

BACKGROUND: The present study investigated the effect of two-step heat treatments on the structure of grass carp myofibrillar proteins (MPs) and their binding ability for selected aldehydes (hexanal, heptanal, octanal and nonanal). RESULTS: Within 30 min of the first heating step at 40 °C and 5-10 min of the second heating step at 90 °C, the enhancement of the flavor-binding ability was likely explained by the increases in surface hydrophobicity and total sulfhydryl content due to the unfolding of secondary structures of MPs through exposure of hydrophobic amino acids and sulfhydryl groups. Nevertheless, lengthy heating at 90 °C accelerated the aggregation of unfolded MPs and reduced the hydrophobic bonding sites, thus weakening the hydrophobic interactions and decreasing the resultant binding ability of MPs with aldehydes. CONCLUSION: The binding ability of aldehydes to MPs was found to be strongly influenced by changes in protein structure and surface during the two-step heating process. The results provided insight into improving the flavor characteristics of freshwater fish surimi products. © 2019 Society of Chemical Industry.

Virulence, Molecular Diversity, and Mating Type of Curvularia lunata in China.

Curvularia leaf spot (CuLS), caused by Curvularia lunata, is a devasting foliar disease in the maize-growing regions of China. Resistant varieties were widely planted in these regions in response to CuLS. However, over time, C. lunata has gradually adapted to the selective pressure and, in recent years, the incidence of CuLS has increased. To assess the correlation between virulence and genetic diversity, a total of 111 isolates was collected from 15 maize-growing regions located in nine provinces in China. These isolates were evaluated for virulence on maize using nine differential hosts: Shen135, CN165, Mo17, Luyuan92, 78599, Ye478, B73, E28, and Huangzaosi. To evaluate the genetic diversity, 657 polymorphic amplified fragment length polymorphism markers were generated. Results showed that the isolates could be grouped into three pathotypes according to the phenotypic expression of the differential inbred lines. Isolates were clustered into two genetic diversity groups and further divided into subgroups. However, the correlation between virulence and genetic diversity grouping was low. Also, there was a low correlation observed between pathotype and geographic distribution. The ratio of mating type I to mating type II for all isolates was close to 3:4.

Effect of heat treatment on the binding of selected flavor compounds to myofibrillar proteins.

BACKGROUND: The influence of heat-induced structural modifications of grass carp myofibrillar protein (MP) on its ability to bind to selected aldehydes (hexanal, heptanal, octanal and nonanal) was investigated. The interactions of MP and flavor compounds were investigated using HS-GC-MS, intrinsic fluorescence spectra, Raman spectra, SDS-PAGE, turbidity, total sulfhydryl content and surface hydrophobicity. RESULTS: The ability to bind to aldehydes was strongly influenced by changes in the structure and surface of proteins during the heating process (0-30 min). During the first 0-10 min of heating, the flavor-binding ability increased, which is likely attributable to increased surface hydrophobicity and total sulfhydryl content, and to the unfolding of secondary structures of MP by exposure to reactive amino acids, sulfhydryl groups and hydrophobic bonding sites. Nevertheless, lengthy heating (>10 min) caused protein refolding and accelerated aggregation of protein, thus reducing hydrophobic interactions and weakening the resultant capacity of MP to bind to flavor compounds. CONCLUSION: The results suggested that hydrophobic interactions were enhanced upon short-term heating, whereas long-term heating weakend them. The results provide information concerning improvement of the flavor profile of freshwater fish surimi products. © 2019 Society of Chemical Industry.

[The study of peri-operative chemotherapy in stage I-IIIa NSCLC].

OBJECTIVE: A number of studies had evaluated the benefit of neoadjuvant chemotherapy combined surgery on stage IIIa-IIIb NSCLC, survival benefit was found in several papers. We attempt to evaluate the survival and prognosis of cisplatinum-based schedule as peri-operative CT for resectable stage I-IIIa NSCLC. METHODS: A prospective, randomized, multicenter study was conducted by Shanghai Lung Cancer Team (supported by Shanghai Branch of Discipline Foundation) since 1995-1997 for 211 cases of stage I-IIIa NSCLC with curative resection (99 stage I, 47 stage II, 65 stage III), age of or= 80, staged by 1997 AJC TNM Criteria. They were randomized to be 103 cases with 1 - 2 cycles of pre-operative CT and 108 cases with no pre-operative CT, 2 - 4 cycles of post-operative CT were used for stage II and stage IIIa NSCLC, it was totally 4 cycles of MVP or MOP CT schedule each case. Follow-up team had been trained, the follow-up rate should be >or= 95%, last follow-up date was March of 2002. Lobectomy was performed for most patients. Accumulated survival, log rank, MST, Cox uni-variance and multi-variance analyses were used as statistics for evaluation. RESULTS: The two arms were well balanced for baseline demographic and clinical characteristics (P > 0.05 for all). Stage I NSCLC had the best year-survival in whole patients. No statistical survival difference was found between the group with pre-op CT and with no pre-op CT, P = 0.074, 0.087 and 0.097, respectively, 5-year survival rates were of 31.98%:36.68%. In various stage, a statistical survival difference was only shown in stage IINSCLC, P = 0.042, 5-year survival rates and MST were worse in the group with pre-operation CT, 20%:65.2% and 24 months:48 months, respectively, but no difference was seen in stage I and stage IIIa NSCLC. Stage and post-operation CT were the only two meaningful parameters with statistical survival difference calculated by multi-variance analyses, P = 0.000 all, but no difference was found in others 4 parameters (age, sex, type and pre-operation CT). The response rate of pre-operation CT was of 50%. Though there was no statistical difference, the responders were with slightly better year-survival rates than MR + NR patients, 38.9% and 33.3%, respectively. In the cases with pathological "T" down stage and "T" unchanged after pre-operation CT had a better yr-survival rates than "T" up-stage, P = 0.03, 5-year survival rates were of 41.67%, 40.51% and 11.76%, respectively, thus, effective chemotherapy might be beneficial to survival. Besides, in the cases with >or= 3 cycles of post-operation CT have better survival rates than less cycles. CONCLUSION: A prospective, randomized, multicenter peri-operation CT study for stage I-IIIa NSCLC conducted in Shanghai, China., it showed there had no benefit in survival between with pre-operation CT arm and with no pre-operation CT arm. In stage II NSCLC, pre-operation CT cases had a worse year-survival than with no pre-operation CT, P = 0.042, but no difference was seen in stage I and stage IIIa NSCLC. The responder of CT and "T" down stage, "T" unchanged had better survival rates than those of not response and "T" up-stage. From multivariate analyses, stage and post-operation CT were the two meaningful parameters to year-survival, >or= 3 - 4 cycles of post-operation CT had a better statistical higher year-survival than less cycles. Nutrition, supportive treatment, immunity status and prevention of toxicity might be the next study worthy to conduct, for CT combined with OP.