Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 557
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Control Release ; 321: 654-668, 2020 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-32114092

RESUMO

Persistent high-risk HPV infection is the main factor for cervical cancer. HPV E7 oncogene plays an important role in HPV carcinogenesis. Down-regulation of E7 oncogene expression could induce growth inhibition in HPV-positive cells and thus treats HPV related cervical cancer. Here we developed a non-virus gene vector based on poly(amide-amine)-poly(ß-amino ester) hyperbranched copolymer (hPPC) for the delivery of CRISPR/Cas9 system to specifically cleave HPV E7 oncogene in HPV-positive cervical cancer cells. The diameter of polyplex nanoparticles (NPs) formed by hPPCs/linear poly(ß-amino ester) (PBAE) and plasmids were approximately 300 nm. These hPPCs/PBAE-green fluorescence protein plasmids polyplex NPs showed high transfection efficiency and low toxicity in cells and mouse organs. By cleaving HPV16 E7 oncogene, reducing the expression of HPV16 E7 protein and increasing intracellular retinoblastoma 1 (RB1) amount, hPPCs/PBAE-CRISPR/Cas9 therapeutic plasmids polyplex NPs, especially highly branched hPPC1-plasmids polyplex NPs, exhibited strong growth inhibition of cervical cancer cells in vitro and xenograft tumors in nude mice. Together, the hPPCs/PBAE polyplex NPs to deliver HPV16 E7 targeted CRISPR/Cas9 system in this study could potentially be applied to treat HPV-related cervical cancer.

2.
Nano Lett ; 2020 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-32155077

RESUMO

Liquid metal forms a thin layer of oxide skin via exposure to oxygen and this layer could be exfoliated by mechanical delamination or gas-injection/solvent-dispersion. Although the room-temperature fabrication of two-dimensional (2D) oxide through gas-injection and water-dispersion has been successfully demonstrated, a synthetic protocol in nonaqueous solvent at elevated temperature still remains as a challenge. Herein we report the mass-production of amorphous 2D SnOx nanoflakes with Bi decoration from liquid Sn-Bi alloy and selected nonaqueous solvents. The functional groups of the solvents play a key role in determining the final morphology of the product and the hydroxyl-rich solvents exhibit the best control toward 2D SnOx. The different solvent-oxide interaction that facilitates this phase-transfer process is further discussed on the basis of DFT calculation. Finally, the as-obtained 2D SnOx is evaluated in electrocatalytic CO2 reduction with high faradaic efficiency (>90%) of formic acid and stable performance over 10 h.

3.
Oncol Lett ; 19(4): 3223-3228, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32218867

RESUMO

It has been found that >90% of oral cancer patients suffer from squamous cell carcinoma (SCC). The 5-year survival rate of SCC is ~50%, despite the availability of different treatments. Sonodynamic therapy (SDT) has been developed as a novel therapy for cancer, resisting bacterial infection and inhibiting atherosclerotic plaque progression. The present study investigated the efficacy of hematoporphyrin monomethyl ether (HMME)-mediated SDT on the A-253 epidermoid cancer cell line. The cytotoxicity of HMME and the survival rate of cells following SDT were examined by the MTT assay. Apoptosis and necrosis of cells were detected using flow cytometry with Annexin V and propidium iodide (PI) staining, and fluorescence microscopy with Hoechst 33258 and PI staining. Intracellular reactive oxygen species (ROS) and Ca2+ levels were measured using a fluorescence microscope based on 2',7'-dichlorofluorescein diacetate and fluo-3/acetoxymethylester, respectively. Results of the MTT assay demonstrated that a lower concentration (<10 µg/ml) of HMME had no significant effect on the A-253 cells, but SDT combined with ultrasonic treatment for 1 min and 10 µg/ml HMME decreased the cell survival rate by 27%. Flow cytometry analysis revealed that A-253 cells in the SDT group had a higher rate of late apoptosis compared with the control group. Furthermore, fluorescence quantitation of apoptotic A-253 cells demonstrated that the percentages of apoptotic cells were increased in the ultrasound and SDT group compared with those in the control group. In the present study, the ROS level in the SDT group was elevated compared with that in the control group. The Ca2+ levels were increased to 181.2 and 268.7% in the ultrasound and SDT groups, respectively, relative to the control group. Taken together, the findings of the present study demonstrated that HMME-SDT significantly induces the apoptosis of A-253 cells together with intracellular ROS generation and Ca2+ overload. Thus, HMME-SDT may be a promising treatment option for patients with SCC.

4.
J Phys Chem Lett ; : 2896-2901, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-32212664

RESUMO

Transition-metal-nitrogen/carbon (TM-N/C) materials are promising alternatives to Pt-based oxygen reduction reaction (ORR) electrocatalysts of fuel cells. Identifying the highly active sites is the prerequisite for the design of high-performance electrocatalysts, in which the density functional theory (DFT) calculation is an important tool. However, the DFT simulation was usually conducted with a charge-neutral model, which is far away from the working condition, that is, under certain potentials. Herein, by using the DFT method with the explicit consideration of electrode potential, we systematically compared the activities of the Fe-N/C moieties previously proposed in the literature and identified the best one. This study not only demonstrates the significance of the electrode potential in computational electrochemistry but also suggests a feasible experimental strategy to increase the ORR performance of Fe-N/C electrocatalysts by creating edges defects and coordinating with the axial ligands on the Fe center, which is of practical significance for exploring the advanced non-precious-metal-based ORR electrocatalysts and related devices.

5.
Pathol Res Pract ; : 152920, 2020 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-32173142

RESUMO

Glioma is the most common form of malignant intracranial tumors. Cyclin-dependent kinase-like 2 (CDKL2) was observed in various regions of the brain, but the specific role of CDKL2 in glioma has not been reported yet. In the present study, the expression of CDKL2 mRNA was detected by real-time QPCR in freshly collected glioma and para-carcinoma tissues, and we collected genomic and clinical data from The Cancer Genome Atlas to determine mRNA expression levels of CDKL2 in the normal brain and glioma samples. Moreover, western blot assay and immunohistochemistry experiments were implemented to identify CDKL2 protein expression, and clinical pathology characteristics from 151 glioma cases and thirty-four para-carcinoma tissues were also examined. The relationship between the levels of CDKL2 expression and clinical data was analyzed. Low mRNA and protein expression of CDKL2 was observed in glioma tissues compared to non-cancerous tissues. In addition, low levels of CDKL2 correlated with Astrocytic type, higher clinical WHO grade, and higher Ki-67 expression in glioma. Low mRNA and protein expression of CDKL2 in glioma predicted an observably shorter overall survival time than high expression. However, as revealed by multivariate analysis, CDKL2 protein expression was not an independent prognostic biomarker for the survival of patients with glioma. Our study firstly determined that low levels of CDKL2 expression are associated with poor clinical diagnosis. Thus, CDKL2 may serve as a prognostic factor of glioma.

6.
Parkinsonism Relat Disord ; 73: 1-2, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32151945

RESUMO

We screened the RFC1 intronic AAGGG repeat expansions in late-onset ataxia cases, MSA patients and controls. The data suggested that no biallelic repeat expansion carrier was found in our cohort and the heterozygous intronic AAGGG repeat expansions may not lead to an increased risk of late-onset ataxia or MSA.

7.
Nat Ecol Evol ; 4(4): 589-600, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32123323

RESUMO

Eighteen of the 20 amino acids are each encoded by more than one synonymous codon. Due to differential transfer RNA supply within the cell, synonymous codons are not used with equal frequency, a phenomenon termed codon usage bias (CUB). Previous studies have demonstrated that CUB of endogenous genes trans-regulates the translational efficiency of other genes. We hypothesized similar effects for CUB of exogenous genes on host translation, and tested it in the case of viral infection, a common form of naturally occurring exogenous gene translation. We analysed public Ribo-Seq datasets from virus-infected yeast and human cells and showed that virus CUB trans-regulated tRNA availability, and therefore the relative decoding time of codons. Manipulative experiments in yeast using 37 synonymous fluorescent proteins confirmed that an exogenous gene with CUB more similar to that of the host would apply decreased translational load on the host per unit of expression, whereas expression of the exogenous gene was elevated. The combination of these two effects was that exogenous genes with CUB overly similar to that of the host severely impeded host translation. Finally, using a manually curated list of viruses and natural and symptomatic hosts, we found that virus CUB tended to be more similar to that of symptomatic hosts than that of natural hosts, supporting a general deleterious effect of excessive CUB similarity between virus and host. Our work revealed repulsion between virus and host CUBs when they are overly similar, a previously unrecognized complexity in the coevolution of virus and host.

8.
Hum Gene Ther ; 31(5-6): 325-338, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32024383

RESUMO

Refractoriness to conventional chemotherapy is a major challenge in the treatment of advanced ovarian cancer (OC). There is increasing evidence that mitochondrial priming correlates with cisplatin response in various cancers. Notably, Bim and Bid, two of the proapoptotic BH3-only proteins, are recognized as the most effective inducers of mitochondrial priming in OC. In this study, we constructed two tumor-specific oncolytic adenoviruses (Ads) coding for Bim (Ad-Bim) or truncated Bid (Ad-tBid), respectively, and performed gain-of-function assays in nine OC cell lines. Ad-tBid exhibited significant antitumor efficacy than the controls. On addition of Ad-tBid pretreatment, mito-primed cells displayed more sensitivity to cisplatin both in vitro and ex vivo. We also found that Ad-tBid induced mitochondrial apoptosis in a Bak-dependent manner. Furthermore, a combined cisplatin plus Ad-tBid therapy markedly inhibited tumor growth in a subcutaneous xenotransplanted tumor model. In mice bearing peritoneal disseminated OC, intraperitoneal administration of Ad-tBid potentiated the antitumor effect of cisplatin. Our findings suggest that Ad-tBid enhances cisplatin response in OC cells, establishing the potential treatment of advanced OC via a combination of cisplatin and Ad-tBid.

9.
Transplantation ; 2020 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-32108751

RESUMO

BACKGROUND: Xenogeneic organ transplantation has been proposed as a potential approach to fundamentally solve organ shortage problem. Xenogeneic immune responses across species is one of the major obstacles for clinic application of xeno-organ transplantation. The generation of glycoprotein galactosyltransferase alpha 1, 3 (GGTA1) knockout pigs has greatly contributed to the reduction of hyperacute xenograft rejection. However, severe xenograft rejection can still be induced by xenoimmune responses to the porcine major histocompatibility complex (MHC) antigens SLA-I and SLA-II. METHODS: We simultaneously depleted GGTA1, ß2M, and CIITA genes using CRISPR-Cas9 technology in Bamma pig fibroblast cells, which were further used to generate GGTA1ß2MCIITA triple knockout (GBC-3KO) pigs by nuclear transfer. RESULTS: The genotype of GBC-3KO pigs was confirmed by PCR and Sanger sequencing, and the loss of expression of α-Gal, SLA-I, and SLA-II were demonstrated by flow cytometric analysis using fluorescent-conjugated BS-IB4-Lectin, anti-ß2-microglobulin, and SLA-DR antibodies. Furthermore, mixed lymphocyte reaction (MLR) assay revealed that peripheral blood mononuclear cells (PBMCs) from GBC-3KO pigs were significantly less effective than WT pig PBMCs in inducing human CD3CD4 and CD3CD8 T cell activation and proliferation. In addition, GBC-3KO pig skin grafts showed a significantly prolonged survival in immunocompetent C57BL/6 mice, when compared to WT pig skin grafts. CONCLUSIONS: Taken together, these results demonstrate that elimination of GGTA1, ß2M, and CIITA genes in pigs can effectively alleviate xenogeneic immune responses and prolong pig organ survival in xenogenesis. We believe this work will facilitate future research in xenotransplantation.

10.
Mikrochim Acta ; 187(3): 162, 2020 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-32048050

RESUMO

Nitrogen-doped flower-like carbon superstructures (NPC-F) are prepared via carbonizing self-assembled polyimide nanosheets. SEM, TEM, XPS, and N2 sorption methods are adopted to characterize the flower-like structure. NPC-F exhibits adsorption selectivity for hemoglobin (Hb) because the specific pyridinic N groups of NPC-F could coordinate with the sixth vacancy of ferrous ion in hemoglobin. The adsorption behavior fits well with Langmuir model with a maximum adsorption capacity of 360.0 mg g-1 and the adsorbed Hb could be lightly stripped from the NPC-F nanospheres surface by 0.5 wt% CTAB solution. Circular dichroism spectra indicate no obvious conformation changing of Hb during purification process by NPC-F nanospheres. Five cycles of a continuous adsorption/desorption experiment demonstrate the reusability of NPC-F as adsorbent for Hb. The prepared NPC-F superstructures are then employed for the isolation of Hb from human whole blood sample, obtaining high-purity Hb as demonstrated by sodium dodecyl sulfate polyacrylamide gel electrophoresis assays. Graphical abstractNitrogen-doped flower-like carbon superstructure (NPC-F) is used to isolate target protein. NPC-F exhibits highly selective capture capacity towards hemoglobin because the specific pyridinic N groups of NPC-F could coordinate with the sixth vacant coordinating position of Fe2+ in hemoglobin.

11.
J Neurol Sci ; 411: 116691, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-31982778

RESUMO

BACKGROUND: Mutations in CAPN1 have recently been reported to cause the spastic paraplegia 76 (SPG76) subtype of hereditary spastic paraplegia (HSP). To investigate the role of CAPN1 in spastic paraplegia and other neurodegenerative diseases, including spinocerebellar ataxia (SCA), early-onset Parkinson's disease (EOPD), and amyotrophic lateral sclerosis (ALS) we conducted a mutation analysis of CAPN1 in a cohort of Chinese patients with SPG, SCA, EOPD, and ALS. METHODS: Variants of CAPN1 were detected in the three cohorts by Sanger or whole-exome sequencing, and all exons and exon-intron boundaries of CAPN1 were analysed. RESULTS: A novel CAPN1 splicing variant (NM_001198868: c.338-1G > A) identified in a familial SPG/SCA showed a complex phenotype, including spastic paraplegia, ataxia, and extensor plantar response. This mutation was confirmed by Sanger sequencing and completely co-segregated with the phenotypes. Sequencing of the cDNA from the three affected patients detected a guanine deletion (c.340_340delG) that was predicted to result in an early stop codon after 61 amino acids (p. D114Tfs*62). No CAPN1 pathogenic mutation was found in the EOPD or ALS groups. CONCLUSION: Our data reveal a novel CAPN1 mutation found in patients with SPG/SCA and emphasize the spastic and ataxic phenotypes of SPG76, but CAPN1 may not play a major role in EOPD and ALS.

12.
Inflammation ; 43(1): 32-43, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31894450

RESUMO

Air pollution events frequently occur in China during the winter. Most investigations of pollution studies have focused on the physical and chemical properties of PM2.5. Many of these studies have indicated that PM2.5 exacerbates asthma or eosinophil inflammation. However, few studies have evaluated the relationship between bacterial loads in PM2.5, and especially pathogenic bacteria and childhood asthma. Airborne PM2.5 samples from heavily polluted air were collected in Hangzhou, China between December 2014 and January 2015. PM2.5 and ovalbumin (OVA) were intratracheally administered twice in 4-week intervals to induce the allergic pulmonary inflammation in adolescent C57/BL6 mice. PM2.5 exposure caused neutrophilic alveolitis and bronchitis. In the presence of OVA, the levels of the Th2 cytokines IL-4, IL-12, and IL-17 were significantly increased in bronchoalveolar lavage fluids (BALF) after PM2.5 exposure, while eosinophil infiltration and mucin secretion were also induced. In addition to adjuvant effects on OVA-induced allergic inflammation, PM2.5 exposure also led to the maturation of dendritic cells. These results suggest that PM2.5 exposure may aggravate lung eosinophilia and that PM2.5-bound microbial can exacerbate allergic and inflammatory lung diseases.

13.
J Hazard Mater ; 384: 121482, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31668762

RESUMO

Natural and synthetic progestins are emerging endocrine disruptors that can be transported from livestock farms and agricultural fields to receiving waters via surface runoff. The transformation of progestins during transport is expected to affect the efficiencies of runoff management systems. Therefore, this study explored the sorption, transport, and transformation of progesterone, norethisterone acetate, medroxyprogesterone acetate, cyproterone acetate, dydrogesterone, and norethisterone in agricultural soil-water systems. The sorption coefficients and retardation factors (R) were positively correlated with the progestin hydrophobicities, indicating that hydrophobic interactions dominated the sorption and transport processes. During transport, dydrogesterone and progesterone were transformed into 9-10 products. The breakthrough curves of the parents and products exhibited periodical patterns over extended times. Specifically, the R values of the parents and products were positively correlated with chromatographic retention times (hydrophobicities) when the products were generated before transport. In contrast, a negative correlation (R2 = 0.75-0.88) was observed when products were successively generated during transport, indicating that the transformation kinetics changed the retardation of these solutes in the columns. These observations also demonstrated that the transport potential estimates based on traditional metrics of steroid hydrophobicity are not always accurate and that runoff management measures are less effective for metastable progestins.

14.
Bioorg Chem ; 94: 103413, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791679

RESUMO

A series of new ferulic acid derivatives were designed, synthesized and evaluated as multi-target inhibitors against Alzheimer's disease. In vitro studies indicated that most compounds showed significant potency to inhibit self-induced ß-amyloid (Aß) aggregation and acetylcholinesterase (AChE), and had good antioxidant activity. Specifically, compound 4g exhibited the potent ability to inhibit cholinesterase (ChE) (IC50, 19.7 nM for hAChE and 0.66 µM for hBuChE) and the good Aß aggregation inhibition (49.2% at 20 µM), and it was also a good antioxidant (1.26 trolox equivalents). Kinetic and molecular modeling studies showed that compound 4g was a mixed-type inhibitor, which could interact simultaneously with the catalytic anionic site (CAS) and the peripheral anionic site (PAS) of AChE. Moreover, compound 4g could remarkably increase PC12 cells viability in hydrogen peroxide-induced oxidative cell damage and Aß-induced cell damage. Finally, compound 4g had good ability to cross the BBB using the PAMPA-BBB assay. These results suggested that compound 4g was a promising multifunctional ChE inhibitor for the further investigation.

15.
Brain ; 143(1): 222-233, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31819945

RESUMO

Essential tremor is one of the most common movement disorders. Despite its high prevalence and heritability, the genetic aetiology of essential tremor remains elusive. Up to now, only a few genes/loci have been identified, but these genes have not been replicated in other essential tremor families or cohorts. Here we report a genetic study in a cohort of 197 Chinese pedigrees clinically diagnosed with essential tremor. Using a comprehensive strategy combining linkage analysis, whole-exome sequencing, long-read whole-genome sequencing, repeat-primed polymerase chain reaction and GC-rich polymerase chain reaction, we identified an abnormal GGC repeat expansion in the 5' region of the NOTCH2NLC gene that co-segregated with disease in 11 essential tremor families (5.58%) from our cohort. Clinically, probands that had an abnormal GGC repeat expansion were found to have more severe tremor phenotypes, lower activities of daily living ability. Obvious genetic anticipation was also detected in these 11 essential tremor-positive families. These results indicate that abnormal GGC repeat expansion in the 5' region of NOTCH2NLC gene is associated with essential tremor, and provide strong evidence that essential tremor is a family of diseases with high clinical and genetic heterogeneities.

16.
Orthop Surg ; 12(1): 74-85, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31885193

RESUMO

OBJECTIVE: To investigate the clinical efficacy and advantages of the SuperPATH minimally invasive approach to total hip arthroplasty in the treatment of femoral neck fractures in the elderly. METHODS: From January 2016 to September 2018, 110 cases of elderly patients with femoral neck fractures were included in the present study. According to the method of operation, the patients were divided into two groups for comparison. There were 55 cases of the SuperPATH minimally invasive approach to total hip arthroplasty and 55 cases with the conventional posterolateral approach to total hip arthroplasty. The operation time, the length of incision, the amount of operative blood loss, the hospitalization time, and the hospitalization cost were compared between the two groups. The position of total hip prosthesis was observed during the follow-up period. All patients were evaluated for the degree of hip joint pain and the function of the hip joint using the visual analog score (VAS) and the Harris score at 1 week, 1 month, 3 months, 6 months, and 12 months after the operation. RESULTS: All patients were followed up for at least 12 months. The operation time was 108.58 ± 15.87 min in the SuperPATH group and 102.51 ± 19.61 min in the conventional group. The length of incision was 6.65 ± 1.53 cm in the SuperPATH group and 17.08 ± 1.40 cm in the conventional group. The amount of operative blood loss was 147.51 ± 28.84 mL in the SuperPATH group and 170.22 ± 25.34 mL in the conventional group. The hospitalization time was 10.05 ± 2.52 days in the SuperPATH group and 13.36 ± 3.39 days in the conventional group. The hospitalization cost was 6871.78 ± 141.63 dollars in the SuperPATH group and 7791.09 ± 184.88 dollars in the conventional group. Compared with the conventional group, the SuperPATH group had shorter incision length, less blood loss, shorter hospitalization time, and lower hospitalization cost. There was significant difference between the two groups (P < 0.05). In the two groups, there were no complications such as infection, lower extremity venous thrombosis, prosthesis loosening, periprosthetic fracture, and dislocation during the follow-up period. The VAS score was 4.45 ± 0.94 in the SuperPATH group and 4.89 ± 0.79 in the conventional group at 1 week after the operation. There was significant difference between the two groups (P < 0.05). The Harris score was 75.36 ± 3.36 and 80.25 ± 3.09 in the SuperPATH group and 68.80 ± 3.25 and 77.35 ± 3.77 in the conventional group at 1 week and 1 month after the operation, respectively. There was significant difference between the two groups (P < 0.05). In the analysis of the operation time, the VAS score at 1 month, 3 months, 6 months, and 12 months after the operation, and the Harris score at 3 months, 6 months, and 12 months after surgery, there was no significant difference between the two groups (P > 0.05). CONCLUSION: The SuperPATH minimally invasive approach to total hip arthroplasty is an ideal method for the treatment of femoral neck fractures in the elderly. This method has the advantages of the relatively simple operation, short incision, less blood loss, and less trauma. The patients had short hospitalization times, low hospitalization costs, and good recovery of hip joint function.

17.
Ying Yong Sheng Tai Xue Bao ; 30(11): 3735-3744, 2019 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-31833686

RESUMO

To examine the effects of elevated CO2 concentrations on chlorophyll fluorescence of rice leaf, a field experiment was conducted with automatic control system of CO2 concentration in open top-chambers (OTCs). There were three treatments, including atmospheric CO2 concentration (CK), CK+80 µmol·mol-1 CO2 (T1), and CK+200 µmol·mol-1 CO2 (T2). The fast chlorophyll fluorescence induction dynamic curves of flag leaves were measured using the plant efficiency analyzer at the main growth stages of rice. The results showed that T1 treatment significantly increased quantum yield for electron transfer (φEo), maximum photochemical efficiency (Fv/Fm), and performance index (PIABS), but decreased quantum yield for energy dissipation (φDo) at the flowe-ring, milk grain, ripening, and full ripeness stages. The values of φEo, Fv/Fm, and PIABS were increased by 7.3%-23.3%, 3.1%-7.1%, and 46.2%-93.0%, respectively. The φDo values were decreased by 10.3%-20.5%. T2 treatment significantly decreased φEo, Fv/Fm, PIABS by 68.7%, 41.4%, and 93.4%, respectively, but increased φDo by 78.4% at the jointing stage. T2 treatment significantly increased φEo, Fv/Fm, PIABS by 11.6%-19.8%, 4.8%-6.8%, and 53.0%-72.6%, respectively, and decreased φDo by 7.7%-19.4% at the flowering, milk grain, and ripening stages. Our results suggested that elevated CO2 concentration (80, 200 µmol·mol-1) would promote photosynthetic electron transport of PS2 in flag leaves of rice.


Assuntos
Oryza , Dióxido de Carbono , Clorofila , Fluorescência , Fotossíntese , Folhas de Planta
18.
Ying Yong Sheng Tai Xue Bao ; 30(11): 3795-3803, 2019 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-31833693

RESUMO

With the increase of global environmental changes and intensive anthropogenic activities, it is important to maintain and improve soil function. Here, we evaluated the effects of environmental stress (i.e., drying, high temperature and the combination of drying and high temperature) on soil functional stability (resistance and resilience) under three kinds of water management mea-sures, which included conventional-flooded cultivation, non-flooded with uncovered cultivation and non-flooded with straw mulching. Results showed that, compared to single environmental stress (drying or high temperature), combined stress led to lower soil fungal biomass, bacterial biomass, basal respiration, and soil functional resistance, and higher contents of dissolved organic carbon (DOC) and NH4+-N after one day treatment of stress. Combined stress significantly decreased soil functional resilience after 56 days treatment of stress. Results from the correlation analysis showed that bacterial and fungal biomass were significantly related to soil resistance and resilience. Different water management measures could regulate the effects of environmental stress on soil functional stability. Non-flooded with straw mulching treatment significantly increased the contents of soil DOC, NH4+-N, fungal biomass and bacterial biomass, resulting in higher soil functional resistance and resilience compared with conventional-flooded cultivation and non-flooded with uncovered cultivation under both single and combined stress. In summary, non-flooded with straw mulching could improve soil functional stability under environmental stress, and it could be a suitable agricultural management for non-continuously flooded rice cultivation under multiple stresses.


Assuntos
Oryza , Solo , Agricultura , Biomassa , Água , Abastecimento de Água
19.
Chin J Nat Med ; 17(12): 935-944, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31882049

RESUMO

Bipolarins A-H (1-8), eight new tetracyclic ophiobolin-type sesterterpenes featuring a rare oxaspiro[4.4]nonane moiety, were isolated from cultures of fungus Bipolaris sp. TJ403-B1. Their structures and absolute configurations were elucidated by comprehensive spectroscopic analyses, single-crystal X-ray diffraction experiments, electronic circular dichroism and 13C NMR calculations. Additionally, compound 5 exhibited significant selective antimicrobial activity against Enterococcus faecalis with an MIC value 8 µg·mL-1.

20.
Huan Jing Ke Xue ; 40(10): 4718-4724, 2019 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854843

RESUMO

In order to investigate the effects of warming and straw application on soil microbial biomass carbon and nitrogen and bacterial community structure, a randomized block experiment was performed. Four treatments were included, namely a control (CK), warming (WA), straw application (SA), and warming and straw application (WS) treatments. The soils were sampled during the soybean (Sep. 23, 2017) and winter wheat (April 21, 2018) growing seasons. The soils were used to determine the microbial biomass C and N content using chloroform fumigation methods, and the bacterial community structure was evaluated using high-throughput sequencing (Illumina HiSeq). Results indicated that there was no significant difference in microbial biomass C between different warming and straw application treatments (P>0.05). The microbial biomass N of the warming treatment was significantly higher than that of control in the soybean field (P<0.01). There were significant differences in the most dominant soil bacteria between treatments in the soybean growing season (P<0.05) at the class, order, family, and genus levels, while there was no difference in the winter wheat growing season. The percentages of dominant Gemmatimonadales, Gemmatimonadaceae, and Sphingomonas in the CK and WA (or SA) treatments were significantly different (P<0.05) in the soybean growing season. There was a significant (P<0.05) difference in the dominant Gammaproteobacteria between the CK and WA treatments in the winter wheat growing season. The observed number of species, Shannon index, Simpson index, and Chao1 index were lowest in the warming plots in the soybean growing season and highest in the warming and straw application plots in the winter wheat growing season. The Shannon index for the WA plots was significantly higher than in the WS plots in the soybean growing season (P<0.05). The observed number of species, Shannon index, Simpson index, and Chao1 index were significantly higher in the soybean plots than in the winter wheat plots (P<0.05), while the abundance was significantly higher in the winter wheat plots than in the soybean plots (P<0.05). The soybean growing season had significantly higher diversity than the winter wheat growing season. The indexes of α diversity were highly significantly correlated with soil microbial biomass C and N in the soybean growing season (P<0.001), while there was no such correlation in the winter wheat growing season. The indices of α diversity were significantly correlated in both the soybean growing season and winter wheat growing season (P<0.05).


Assuntos
Nitrogênio , Microbiologia do Solo , Solo , Agricultura , Biomassa , Carbono , Temperatura Ambiente
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA