Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 126
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Environ Int ; 140: 105757, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32361577

RESUMO

The anaerobic ammonium oxidizing bacteria (anammox) are the hidden culprit behind the excessive nitrogen loss under a favorable environment, since their detection and abundance get disturbed by several unknown factors. This study intends to find the gap between actual anammox working capacity under different water conditions and fertilizers in the laboratory. The 15N-isotopic tracer technique was used to measure anammox and denitrification rate, and anammox community structure was analyzed through high-throughput sequencing with cytochrome cd-1 nitrite reductase functional gene (an_nirS gene, initially found in Candidatus Scalindua). The experiment consisted of four treatments, i.e., (I) CK_ Control, (II) UR_Urea, (III) PM_Pig Manure, and (IV) SRF_ Slow release fertilizer, under two water conditions, i.e., (a) Continuous flooding_ CF, (b) Alternate wetting and drying_ AWD. Results showed that anammox under CF decreased over time by -40.24%, and denitrification increased up to 39.25%. However, anammox activity under AWD increased up to 10.62% with the availability of NO2-, and surprisingly accompanied by the reduction in denitrification loss (-31.97%), being the most critical factor. We found that soil nifH and AOB genes were strongly favorable for anammox activity, while we observed the presence of anammox and AOB genes co-existing at the same time in paddy soil. The high-throughput sequencing with an_nirS functional gene showed a much higher diversity of anammox genera ever reported, mostly uncultured and unidentified. We concluded that water management is more prominent than fertilizer for anammox, and the most critical factor is the duration of AWD cycle, because of short term air supply could boost anammox activity and gene abundance, and could reduce denitrifier activity as well as nirK gene abundance.

2.
Bioethics ; 34(6): 593-601, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32469104

RESUMO

This paper examines caregiving for sick older family members in the context of socio-economic transformations in rural China, combining empirical investigation with normative inquiry. The empirical part of this paper is based on a case study, taken from fieldwork in a rural Chinese hospital, of a son who took care of his hospitalized mother. This empirical study highlighted family members' weiqu (sense of unfairness)-a mental status from experiencing mistreatment and oppression in family care, yet with constrained power to explicitly protest or make care-related choices. Underpinning people's weiqu and constrained choice, as informed by the conception of structural injustice, is the impact of unjust social structures, organized by unfavourable norms, discriminatory social policies and institutions targeting rural populations. By restraining individual choices and capacities in supporting health care for aging populations, these unjust structures create additional difficulties for and discriminations against rural families and their older members. Some policy recommendations are proposed to mitigate structural injustice so as to empower families and promote care for older people in rural settings.

3.
Int J Biol Macromol ; 159: 295-303, 2020 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-32389651

RESUMO

A novel exopolysaccharide (EPS) with high molecular weight (3.65 × 105 Da) and film-forming ability was produced by the strain Kosakonia sp. CCTCC M2018092. Partially acid hydrolyzed EPS (AH-EPS) with high content of fucose was prepared and exhaustively characterized. The molecular weight of AH-EPS was determined to be 3.47 × 104 Da. GC-MS and HPLC analyses indicated that AH-EPS is composed of L-fucose, d-glucose, D-galactose, D-glucuronic acid and pyruvic acid in the molar ratio of 2.03:1.00:1.18:0.64:0.67. Chemical and NMR analyses revealed that AH-EPS is an anionic heteropolysaccharide, with a major linkage structural motif as follows. Utilizing AH-EPS as reducing and stabilizing agent, silver nanoparticles (AH-EPS@Ag NPs) with uniform size (diameter about 20 nm) were synthesized through a green method. A hybrid film containing EPS and AH-EPS@Ag NPs was further prepared, and its antibacterial effectiveness to Staphylococcus aureus was confirmed. Taken together, this work revealed the structural characteristics of a novel fucose-rich polysaccharide, with good potential in developing new biodegradable antibacterial film.

4.
Nurs Ethics ; : 969733020912517, 2020 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-32242477

RESUMO

BACKGROUND: The pressing issue of aged care has made gendered caregiving a growing subject of feminist bioethical enquiry. However, the impact of feminism on empirical studies in the area of gendered care in Chinese sociocultural contexts has been less influential. OBJECTIVES: To examine female members' lived experiences of gendered care in rural China and offer proper normative evaluation based on their experiences. RESEARCH DESIGN: This article adopted an empirical ethical approach that integrates ethnographical investigation and feminist ethical inquiry. PARTICIPANTS AND RESEARCH CONTEXT: This article focused on three cases of gendered caregiving for sick older members collected from a 6-month fieldwork conducted in a primary hospital in rural China. ETHICAL CONSIDERATION: Approval was obtained from the university ethics committee. FINDINGS: The empirical work highlights caregivers' voices of weiqu (a sense of unfairness) resulting from their constrained choice when being pressured to engage in caregiving, which is associated with a disadvantageous socio-institutional and structural backdrop in current rural China. Informed by the conception of structural injustice, the normative analysis of this article traced various forms of social norms, structural deficiencies and ageing welfare institutions, as they intertwine and transmit into additional care deficiencies against rural families and their female caregivers. CONCLUSION: This article identified the constraint of gender hierarchy and its intersection with external social structure that exacerbate gendered oppression and exploitation of female labour in rural China. Normatively, this article argues that the current configuration of rural family care, featured by structural impediments and exploration of female labour, is unjust. Some policy recommendations are proposed to empower caregivers and advance care for rural older people.

5.
Artigo em Inglês | MEDLINE | ID: mdl-32210084

RESUMO

This paper examines the experiences of seeking healthcare for rural Chinese older people, a population who experiences the multiple threats of socio-economic deprivation, marginalization, and lack of access to medical care, yet have been relatively overlooked within the existing scholarly literature. Based on ethnographical data collected from six-month fieldwork conducted in a rural primary hospital in Southern China, this paper identifies a widespread discouraging, dispiriting attitude regarding healthcare-seeking for rural older members despite the ongoing efforts of institutional reforms with a particular focus on addressing access to health services amongst rural populations. Such an attitude was expressed by older people's families as well as the public in their narratives by devaluing older members' health care demands as "unworthy of care and treatment" ("buzhide zhi" in Chinese). It was also internalized by older people, based on which they deployed a family-oriented health-seeking model and strategically downgraded their expectation on receiving medical care. Moreover, underpinning this discouragement and devaluation, as well as making them culturally legitimate, is the social expectation of rural older people to be enduring and restrained with health-seeking. Simultaneously, this paper highlights the sourc2e of institutional and structural impediments, as they intersect with unfavorable socio-cultural values that normalize discouragement and devaluation.

6.
Environ Pollut ; 262: 114314, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32179213

RESUMO

Ammonia (NH3) emissions could have significant impacts on both ecosystems and human health. Ice cores from the Tibetan Plateau contain information about past ammonium (NH4+) deposition, which could yield important insights into historical NH3 emissions in the surrounding source regions as well as long-distance NH4+ aerosol transport via atmospheric circulation. In this paper, we present a high-resolution atmospheric NH4+ deposition record for the period, 1951-2008, reconstructed from the Zangser Kangri (ZK) ice core in the northern Tibetan Plateau. An empirical orthogonal function (EOF) analysis of major soluble ions (NH4+, NO3-, SO42-, Cl-, Na+, K+, Mg2+ and Ca2+) reveals that EOF 1 has significant loadings of all ions, therefore representing common transport pathways, while EOF 2 is only significantly loaded by NH4+ (0.86) and NO3- (0.35), suggesting a unique signal possibly representing emissions from the surrounding terrestrial ecosystems on the Tibetan Plateau. Backward trajectory analysis indicates that the air masses over the ZK ice core drilling site primarily come from the northwestern Indian Peninsula. NH3 emissions from agricultural activities in this area likely contribute to the NH4+ deposition of the ZK ice core via the Indian monsoon. Correlations between EOF 2 time series and temperature, normalized difference vegetation index (NDVI) suggest that increasing temperature and vegetation after 1980 likely promoted NH3 emissions from terrestrial ecosystems. Our results provide a reliable and valuable assessment of NH4+ deposition from human activities and terrestrial ecosystems in the ZK ice core, and help in understanding air pollution over the past few decades in the northern Tibetan Plateau.

7.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 38(1): 17-22, 2020 Feb 01.
Artigo em Chinês | MEDLINE | ID: mdl-32037761

RESUMO

OBJECTIVE: To study the effect of the focal adhesion kinase inhibitor TAE226 on epithelial-mesenchymal transition (EMT) in human oral squamous cell carcinoma (OSCC) cell line. METHODS: HSC-3 and HSC-4 cells were cultured with TAE226 under different concentrations (0, 1, 5, and 10 µmol·L⁻¹) for 24, 48, and 72 h. Real-time quantitative polymerase chain reaction was performed to detect the mRNA expressions of E-cadherin and Vimentin. The protein expressions of E-cadherin and Vimentin were determined by Western blot assay after 48 h of TAE226 treatment. RESULTS: Real-time quantitative polymerase chain reaction showed that increasing the TAE226 dose and reaction time resulted in increased and decreased E-cadherin and Vimentin mRNA expressions, respectively (P<0.05). Western blot assays showed that increasing the TAE226 dose resulted in increased and decreased E-cadherin and Vimentin protein expressions, respectively (P<0.05). CONCLUSIONS: TAE226, which is expected to be an effective drug for OSCC treatment, can effectively inhibit the EMT of the OSCC cell line.


Assuntos
Carcinoma de Células Escamosas , Neoplasias Bucais , Caderinas , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal , Proteína-Tirosina Quinases de Adesão Focal , Humanos , Morfolinas , Vimentina
8.
BMC Med Genet ; 21(1): 14, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31941453

RESUMO

BACKGROUND: The DENND1A gene is one of the most important sites associated with polycystic ovary syndrome (PCOS). We attempted to analyze the correlation between five single nucleotide polymorphisms (SNPs) in the DENND1A gene and the development of PCOS. METHODS: A total of 346 PCOS patients and 225 normal ovulatory women were involved in the case-control study. Clinical variables and hormones were recorded. According to the Hap Map database, five tagging SNPs (rs2479106, rs2768819, rs2670139, rs2536951 and rs2479102) in the DENND1A gene were identified. The TaqMan probe and the PCR-RFLP (restriction fragment length polymorphism) methods were used for revealing these genotypes. TaqMan Genotype Software was used to analyze the alleles of the five SNPs. RESULTS: Linkage disequilibrium and the gene frequency analysis demonstrated that the CCGGG haplotype might increase the risk of PCOS (P = 0.038, OR = 1.89, 95% CI = 1.027-3.481). Significant differences were found in genotypic and allelic distributions at the rs2536951 and rs2479102 loci between PCOS women and controls (P <  0.001). The LH levels and LH/FSH ratios were higher in PCOS patients than in the control group. A detailed analysis revealed that for the rs2479106 locus, these two values were significantly different in the control subjects who had AA, AG and GG genotypes (P = 0.013 and P = 0.007, respectively), and for the rs2468819 locus, these two values were significantly different among the PCOS patients with AA, AG and GG genotypes (P = 0.013 and 0.002, respectively). CONCLUSIONS: The tagging SNPs rs2479106 and rs2468819 in the DENND1A gene are associated with PCOS in the Chinese population, whereas rs2670139, rs2536951 and rs2479102 are not correlated with PCOS in the same population.


Assuntos
Proteínas Adaptadoras de Sinalização de Receptores de Domínio de Morte/genética , Estudos de Associação Genética , Predisposição Genética para Doença , Fatores de Troca do Nucleotídeo Guanina/genética , Síndrome do Ovário Policístico/genética , Adulto , Alelos , China/epidemiologia , Feminino , Genótipo , Haplótipos/genética , Humanos , Síndrome do Ovário Policístico/epidemiologia , Síndrome do Ovário Policístico/patologia , Polimorfismo de Nucleotídeo Único/genética , Fatores de Risco
9.
Kidney Blood Press Res ; 45(1): 95-108, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31927554

RESUMO

BACKGROUND/AIMS: Acute kidney injury (AKI) is a common clinical condition that can lead to chronic kidney failure. Although mesenchymal stem cell-derived extracellular vesicles (MSC EVs) are regarded as a potent AKI treatment, the mechanisms underlying their beneficial effects remain unclear. Oct-4 may play an important role in tissue injury repair. We thus hypothesized that oct-4 overexpression might enhance the therapeutic effects of MSC EVs in AKI treatment. METHODS: Renal tubular epithelial cells were cultured in a low oxygen environment, then cocultured with MSC EVs or control medium for 48 h. BrdU and transferase-mediated dUTP nick-end labeling (TUNEL) staining were used to assess cell proliferation and apoptosis. Mice subjected to ischemia reperfusion were randomly divided into 4 groups, then injected with either phosphate-buffered saline (vehicle), EVs, EVs overexpressing oct-4 (EVs+Oct-4), and EVs not expressing Oct-4 (EVs-Oct-4). Blood creatinine (CREA) and urine nitrone levels were assessed 48 h and 2 weeks after injection. After ischemia reperfusion, renal tissues from each group were stained with TUNEL and proliferating cell nuclear antigen (PCNA) to determine the degree of apoptosis and proliferation. Masson trichrome staining was used to evaluate renal fibrosis progression. Snail gene expression was assessed using polymerase chain reaction (PCR). RESULTS: At 48 h after hypoxic treatment, TUNEL and BrdU staining indicated that the EVs+Oct-4 group had the least apoptosis and the most proliferation, respectively. Treatment with EVs overexpressing Oct-4 significantly decreased serum Crea and blood urea nitrogen levels and rescued kidney fibrosis, as indicated by the low proportion of Masson staining, high number of PCNA-positive cells, and low number of TUNEL-positive cells. PCR analysis indicated that Snail was most upregulated in the vehicle group and least upregulated in the EVs+Oct-4 group. CONCLUSIONS: MSC EVs had a pronounced therapeutic effect on ischemic reperfusion injury-related AKI, and Oct-4 overexpression enhanced these therapeutic effects. Our results may inspire a new direction for AKI treatment with MSC EVs.

10.
Environ Microbiol ; 22(1): 229-242, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31650666

RESUMO

Polymalic acid (PMA) is a novel biopolymer produced by the polyextremotolerant fungus Aureobasidium pullulans. In this study, a GATA-family transcriptional factor, Gat1, which regulates nitrogen uptake and PMA biosynthesis, was investigated. PMA production increased to 11.2% in the mutant overexpressing gat1 but decreased to 49.1% of the PMA titre when gat1 was knocked out from the genome of A. pullulans. Comparative transcriptome analysis of wild-type and mutant strains (∆gat1 and OE::gat1) revealed that 23 common differentially expressed genes were related to oxidative phosphorylation, ribosome biogenesis, and nitrogen metabolism. Under nitrogen-limited stress, regardless of the preferred nitrogen (glutamine, Gln) or non-preferred nitrogen (proline, Pro), 70% of Gat1 in the cells was located in the nucleus-cytoplasm, which resulted in an increase in nitrogen uptake and PMA biosynthesis regulation. Quantitative RT-PCR revealed that glucosekinase (GLK) in the glycolytic pathway and malate synthase (MLS) in the glyoxylate shunt pathway may be cross-regulated by Gat1 and nitrogen concentration (Gln or Pro), Therefore, glk was overexpressed in mutant strain (OE::gat1), which resulted in an increased PMA titre and yield of 12.6% and 13.0% respectively. These findings indicate that Gat1 may play an important role in the dual regulation of the nitrogen and carbon metabolisms in PMA biosynthesis.

11.
J Control Release ; 316: 66-78, 2019 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-31682913

RESUMO

A self-assembled and oxidation-degradable Janus-prodrug, termed as Bud-ATK-Tem (B-ATK-T), was fabricated by ROS-responsive aromatized thioketal (ATK) linked anti-inflammatory drug budesonide (Bud) and antioxidant tempol (Tem). Benefiting from the hydrophobic interactions and π-π stacking interactions of ATK, prodrug B-ATK-T could self-assemble into nanoparticles (NP) in water containing lecithin and DSPE-PEG2K. The morphology of B-ATK-T NP (approximate 100-120nm) was confirmed to be regular spherical by transmission electron microscope. B-ATK-T NP was endowed high drug loading content with 41.23% for Bud and 15.55% for Tem. The rapid drug release from B-ATK-T NP proceeded in an extensive reactive oxygen species (ROS)-dependent manner. More than 98% of Bud and Tem in B-ATK-T NP could release in the mimic inflammation microenvironment or phorbol-12-myristate-13-acetate (PMA)-stimulated macrophages within short time. The release of drugs in a simultaneous and proportional manner ensures that B-ATK-T NP can increase the combined efficacy of anti-inflammation and anti-oxidation. It is worth noting that B-ATK-T NP could be passively accumulated and dramatically increasing the maximum drugs concentration in the inflamed colon of mice with inflammatory bowel disease (IBD) by oral route, and avoiding potential systemic side effects. B-ATK-T NP could not only relieve colitis via inhibiting the expression of oxidative and proinflammatory mediators more than combination of free drugs, but also significantly reduce colitis-caused death. Taken together, the self-assembled, Janus-prodrug B-ATK-T NP is a promising candidate therapies for IBD, even for other inflammatory diseases.

12.
Microbiol Resour Announc ; 8(30)2019 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-31346019

RESUMO

Kosakonia sp. strain CCTCC M2018092 is a fucose-rich exopolysaccharide producer that was isolated from spring water in Chongqing, Southwest China. In this study, the whole-genome sequence and genetic characteristics of this strain were elucidated. This genome contained 4,789,478 bp, with a G+C content of 56.08% (excluding the plasmid). The genome information in this study will facilitate understanding of the mechanism of high yield of fucose-rich exopolysaccharide produced by Kosakonia sp. CCTCC M2018092.

13.
Appl Microbiol Biotechnol ; 103(16): 6519-6527, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31243500

RESUMO

Polymalic acid (PMA) is a biodegradable polymer produced by the polyextremotolerant fungi Aureobasidium pullulans and has been shown to have potential applications in environmental fields. In this work, a high PMA yield mutant FJ-D2 was screened from T-DNA-based mutant libraries and showed a 12.9% increase in PMA titers, which was attributed to decreased the expression of a glycosyltransferase gene (celA), resulting in a 39.5% reduction in cellulose biosynthesis. Untreated waste xylose mother liquor (WXML), an environmental waste generated from the xylitol industry, can be directly used as an economical substrate for PMA production. Using batch-fermentation of FJ-D2, the PMA titer of 57.1 ± 0.02 g/L was produced in a 5-L fermentor, with the highest MA yield of 0.77 g/g mixed sugar. Furthermore, compared with ethylenediaminetetraacetic acid (EDTA), PMA had a comparable cadmium (Cd) removal efficiency (88.7% for EDTA versus 86.0% for PMA), which was not found in the monomer of L-malic acid (MA) monomers. These findings indicated that PMA was an environmentally friendly and biodegradable chelator for soil remediation. Moreover, our results provided an economically competitive process for PMA production from renewable environmental wastes.


Assuntos
Ascomicetos/metabolismo , Resíduos Industriais , Malatos/metabolismo , Polímeros/metabolismo , Xilose/metabolismo , Biotransformação , DNA Bacteriano/genética , Testes Genéticos , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Mutação , Transformação Genética
14.
Water Res ; 160: 296-303, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31154127

RESUMO

Ultraviolet light-emitting diodes (UV-LEDs) are promising alternatives to conventional low-pressure UV (LPUV) lamps, mainly because they contain no toxic mercury and have a potential for less energy consumption and longer lifetime. In this study, UV sources including UV-LEDs (265, 275 and 285 nm) and LPUV (254 nm) were compared in UV/chlorine degradation of an organic contaminant, ronidazole (RNZ). UV-LED/chlorine performed better than LPUV/chlorine at neutral and alkaline pH values for RNZ degradation considering the fluence-based rate constant. However, the wall plug efficiencies of UV-LEDs are relatively low at present and must reach about 20-25% to achieve the same electrical energy per order as the LPUV in UV/chlorine degradation of RNZ at pH 7.5 and 9. Neither the contribution of radical (HO· or Cl·) nor the quantum yield of chlorine could explain the different RNZ degradation rate by UV/chlorine at different wavelengths and pH values, while the chlorine photolysis rate should be the key factor for these phenomena. The effects of common co-existing substances in real water (chloride, bicarbonate and natural organic matter) on UV/chlorine degradation of RNZ were similar at different UV wavelengths. Opposite to other oxidants or reductants, the molar absorption coefficient of chlorine increases when the UV wavelength increases from 254 to 285 nm at neutral and alkaline pH, which makes UV-LED/chlorine one of the best choices for UV-LED-based advanced oxidation/reduction processes.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Cloro , Concentração de Íons de Hidrogênio , Oxirredução , Ronidazole , Raios Ultravioleta
15.
Theranostics ; 9(9): 2541-2554, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31131052

RESUMO

Maximal resection of tumor while preserving the adjacent healthy tissue is particularly important for larynx surgery, hence precise and rapid intraoperative histology of laryngeal tissue is crucial for providing optimal surgical outcomes. We hypothesized that deep-learning based stimulated Raman scattering (SRS) microscopy could provide automated and accurate diagnosis of laryngeal squamous cell carcinoma on fresh, unprocessed surgical specimens without fixation, sectioning or staining. Methods: We first compared 80 pairs of adjacent frozen sections imaged with SRS and standard hematoxylin and eosin histology to evaluate their concordance. We then applied SRS imaging on fresh surgical tissues from 45 patients to reveal key diagnostic features, based on which we have constructed a deep learning based model to generate automated histologic results. 18,750 SRS fields of views were used to train and cross-validate our 34-layered residual convolutional neural network, which was used to classify 33 untrained fresh larynx surgical samples into normal and neoplasia. Furthermore, we simulated intraoperative evaluation of resection margins on totally removed larynxes. Results: We demonstrated near-perfect diagnostic concordance (Cohen's kappa, κ > 0.90) between SRS and standard histology as evaluated by three pathologists. And deep-learning based SRS correctly classified 33 independent surgical specimens with 100% accuracy. We also demonstrated that our method could identify tissue neoplasia at the simulated resection margins that appear grossly normal with naked eyes. Conclusion: Our results indicated that SRS histology integrated with deep learning algorithm provides potential for delivering rapid intraoperative diagnosis that could aid the surgical management of laryngeal cancer.


Assuntos
Carcinoma de Células Escamosas/diagnóstico por imagem , Aprendizado Profundo , Técnicas Histológicas/métodos , Neoplasias Laríngeas/diagnóstico por imagem , Microscopia Óptica não Linear/métodos , Patologia Cirúrgica/métodos , Automação Laboratorial/métodos , China , Humanos
16.
Gene ; 709: 8-16, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31132514

RESUMO

Aureobasidium pullulans, a yeast-like fungus with strong environmental adaptability, remains a potential host for bio-production of different valuable metabolites. However, its potential application is limited by low-efficient genetic manipulation. In this study, CRISPR/Cas9-mediated genome editing via protoplast-based transformation system was developed. To test CRISPR/Cas9 mediated genomic mutagenesis, the orotidine 5-phosphate decarboxylase (umps) gene was used as a counter-selectable selection marker. By co-transforming of two plasmids harboring cas9 gene and a guide RNA targeting umps, respectively, the CRISPR/Cas9 system could significantly increase frequency of mutation in the targeting site of guide RNA. To further validate that CRISPR/Cas9 stimulated homologous recombination with donor DNA, a color reporter system of beta-glucuronidase (gus) gene was developed for calculating positive mutation rate. The results showed that positive mutation rate with CRISPR/Cas9 system was ~40% significantly higher than only with the donor DNA (~4%). Furthermore, the different posttranscriptional RNA processing schemes were analyzed by compared the effects of flanking gRNA with self-cleaving ribozymes or tRNA. The result demonstrated that gRNA processed by self-cleaving ribozymes achieves higher positive mutant rate. This study provided foundation for a simple and powerful genome editing tool for A. pullulans. Moreover, a counter-selectable selection marker (umps) and a color reporter system (gus) were being developed as genetic parts for strain engineering.


Assuntos
Ascomicetos/genética , Sistemas CRISPR-Cas/genética , Edição de Genes/métodos , Genoma Fúngico , Protoplastos/metabolismo , Transformação Genética , Organismos Geneticamente Modificados , Saccharomyces cerevisiae/genética
17.
Biomed Res Int ; 2019: 2436924, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30834257

RESUMO

The prediction of apoptosis protein subcellular localization plays an important role in understanding the progress in cell proliferation and death. Recently computational approaches to this issue have become very popular, since the traditional biological experiments are so costly and time-consuming that they cannot catch up with the growth rate of sequence data anymore. In order to improve the prediction accuracy of apoptosis protein subcellular localization, we proposed a sparse coding method combined with traditional feature extraction algorithm to complete the sparse representation of apoptosis protein sequences, using multilayer pooling based on different sizes of dictionaries to integrate the processed features, as well as oversampling approach to decrease the influences caused by unbalanced data sets. Then the extracted features were input to a support vector machine to predict the subcellular localization of the apoptosis protein. The experiment results obtained by Jackknife test on two benchmark data sets indicate that our method can significantly improve the accuracy of the apoptosis protein subcellular localization prediction.


Assuntos
Proteínas Reguladoras de Apoptose/genética , Apoptose/genética , Biologia Computacional , Algoritmos , Sequência de Aminoácidos/genética , Proteínas Reguladoras de Apoptose/ultraestrutura , Proliferação de Células/genética , Bases de Dados de Proteínas , Humanos , Transporte Proteico/genética , Máquina de Vetores de Suporte
18.
Crit Rev Biotechnol ; 39(3): 408-421, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30741018

RESUMO

Some microorganisms naturally produce ß-poly(l-malic acid) (PMA), which has excellent water solubility, biodegradability, and biocompatibility properties. PMA has broad prospective applications as novel biopolymeric materials and carriers in the drug, food, and biomedical fields. Malic acid, a four-carbon dicarboxylic acid, is widely used in foods and pharmaceuticals, as a platform chemical. Currently, malic acid produced through chemical synthesis and is available as a racemic mixture of l- and d-forms. The d-form malic acid exhibits safety concerns for human consumption. There is extensive interest to develop economical bioprocesses for l-malic acid and PMA production from renewable biomass feedstocks. In this review, we focus on PMA biosynthesis by Aureobasidium pullulans, a black yeast with a large genome containing genes encoding many hydrolases capable of degrading various plant materials. The metabolic and regulatory pathways for PMA biosynthesis, metabolic engineering strategies for strain development, process factors affecting fermentation kinetics and PMA production, and downstream processing for PMA recovery and purification are discussed. Prospects of microbial PMA and malic acid production are also considered.


Assuntos
Ascomicetos/metabolismo , Reatores Biológicos , Fermentação/genética , Malatos/metabolismo , Polímeros/metabolismo , Ascomicetos/genética , Biomassa , Catálise , Hidrólise , Cinética
20.
Sci Total Environ ; 650(Pt 1): 210-215, 2019 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-30196221

RESUMO

Pulsed ultraviolet (UV) irradiation has presented enhanced inactivation efficiency in water disinfection and food decontamination. As an emerging UV source, UV light-emitting diodes (UV-LEDs) are an attractive alternative for pulsed irradiation because they can be turned on and off with a high and adjustable frequency. In this study, disinfection efficiencies of pulsed and continuous UV-LED irradiation were compared for Escherichia coli (E. coli) inactivation in water using a high power 285 nm LED and low power 265 and 280 nm LEDs. Factors including various duty cycles, pulse frequencies and UV irradiances were evaluated. The log-inactivation of E. coli increased substantially as the duty cycle decreased from 100% to 5% at the same UV dose. For 265 and 280 nm LEDs, the log-inactivation enhancements of pulsed UV irradiation were similar. When a higher irradiance was applied, the energy efficiency enhancement of pulsed UV irradiation became more obvious. The log-inactivation of E. coli enhanced remarkably using high current pulsed irradiation of 280 nm LEDs. Compared to continuous UV irradiation, pulsed UV-LED irradiation is an attractive alternative for E. coli inactivation in water considering energy efficiency.


Assuntos
Desinfecção/métodos , Escherichia coli/efeitos da radiação , Raios Ultravioleta , Microbiologia da Água , Purificação da Água/métodos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA