Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 42
Filtrar
1.
Invest Ophthalmol Vis Sci ; 65(4): 15, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38587443

RESUMO

Purpose: The purpose of this study was to understand how monocular luminance reduction affects binocular balance and examine whether it differentially influences fusion and mixed perception in amblyopia. Methods: Twenty-three normally sighted observers and 12 adults with amblyopia participated in this study. A novel binocular rivalry task was used to measure the phase duration of four perceptual responses (right- and left-tilts, fusion, and mixed perception) before and after a neutral density (ND) filter was applied at various levels to the dominant eye (DE) of controls and the fellow eye (FE) of patients with amblyopia. Phase durations were analyzed to assess whether the duration of fusion or mixed perception shifted after monocular luminance reduction. Moreover, we quantified ocular dominance and adjusted monocular contrast and luminance separately to investigate the relationship between changes in ocular dominance induced by the two manipulations. Results: In line with previous studies, binocular balance shifted in favor of the brighter eye in both normal adults and patients with amblyopia. As a function of the ND filter's density, the duration of fusion and mixed perception decreased in normal controls, whereas that of fusion but not mixed perception increased significantly in patients with amblyopia. In addition, changes in binocular balance from luminance reduction were more significant in more balanced amblyopes or normal observers. Furthermore, shifts in binocular balance after contrast and luminance modulation were correlated in both normal and amblyopic observers. Conclusions: The duration of fusion but not mixed perception increased in amblyopia after monocular luminance reduction in the FE. Moreover, our findings demonstrate that changes in ocular dominance from contrast-modulation and luminance-modulation are correlated in both normal and amblyopic observers.


Assuntos
Ambliopia , Adulto , Humanos , Dominância Ocular , Percepção
2.
Artigo em Inglês | MEDLINE | ID: mdl-38538873

RESUMO

Endo-1,4-ß-xylanase is a key xylanolytic enzyme, and our study aimed to enhance the catalytic properties of Alteromones Macleadii xylanase (Xyn ZT-2) through sequence-guided design approach. Analysis of the amino acid sequence revealed highly conserved residues near the active site, with few differences. Introducing various mutations allowed us to modify the enzyme's catalytic performance. Particularly, the A152G mutation led to a 9.8-fold increase in activity and a 23.2-fold increase in catalytic efficiency. Moreover, A152G exhibited an optimal temperature of 65 °C, 20 °C higher than that of Xyn ZT-2, while the T287S mutant showed a 4.9-fold increase in half-life. These results underscore the role of amino acid evolution in shaping xylanase catalysis. Through targeted sequence analysis and a focused mutation library, we effectively improved catalytic performance, providing a straightforward approach for enhancing enzyme efficiency.

3.
Ophthalmic Physiol Opt ; 44(3): 564-575, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38317572

RESUMO

Short-term monocular deprivation (MD) shifts sensory eye balance in favour of the previously deprived eye. The effect of MD on eye balance is significant but brief in adult humans. Recently, researchers and clinicians have attempted to implement MD in clinical settings for adults with impaired binocular vision. Although the effect of MD has been studied in detail in single-session protocols, what is not known is whether the effect of MD on eye balance deteriorates after repeated periods of MD (termed 'perceptual deterioration'). An answer to this question is relevant for two reasons. Firstly, the effect of MD (i.e., dose-response) should not decrease with repeated use if MD is to be used therapeutically (e.g., daily for weeks). Second, it bears upon the question of whether the neural basis of the effects of MD and contrast adaptation, a closely related phenomenon, is the same. The sensory change from contrast adaptation depends on recent experience. If the observer has recently experienced the same adaptation multiple times for consecutive days, then the adaptation effect will be smaller because contrast adaptation exhibits perceptual deterioration, so it is of interest to know if the effects of MD follow suit. This study measured the effect of 2-h MD for seven consecutive days on binocular balance of 15 normally sighted adults. We found that the shift in eye balance from MD stayed consistent, showing no signs of deterioration after subjects experienced multiple periods of MD. This finding shows no loss of effectiveness of repeated daily doses of MD if used therapeutically to rebalance binocular vision in otherwise normal individuals. Furthermore, ocular dominance plasticity, which is the basis of the effects of short-term MD, does not seem to share the property of 'perceptual deterioration' with contrast adaptation, suggesting different neural bases for these two related phenomena.


Assuntos
Córtex Visual , Adulto , Humanos , Córtex Visual/fisiologia , Privação Sensorial/fisiologia , Visão Ocular , Visão Binocular/fisiologia , Dominância Ocular , Visão Monocular/fisiologia
4.
Insects ; 14(8)2023 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-37623379

RESUMO

The gut bacterial microbiota of insects plays a crucial role in physiological, metabolic, and innate immune processes. In the current study, the gut bacterial communities of an insecticide-susceptible (IS), and a resistant (IR) population of a major legume pest, Megalurothrips usitatus (Bagnall), were evaluated. The 16S rDNA V3 + V4 regions of M. usitatus infected with Beauveria brongniartii along with the intestinal flora of both populations were sequenced based on a High-throughput sequencing platform. Toxicological bioassays revealed that the IR population exhibited resistance to acetamiprid and B. brongniartii isolate SB010 at levels of 138.0-fold and 55.6-fold higher, respectively, compared to the IS population. Through 16S High-throughput sequencing, the results indicate that both resistant populations, as well as B. brongniartii infestation, reduce the number of species of M. usitatus gut microbes. Using KEGG function prediction, it was found that most intestinal bacteria were involved in various metabolic activities, and the abundance of resistant populations was higher than that of sensitive populations. The bacteria in the gut of M. usitatus are mainly involved in various metabolic activities to achieve the degradation of B. brongniartii. This study provides valuable insights into the interaction between gut bacteria, insecticide resistance, and Beauveria. brongniartii infection in Megalurothrips usitatus, which can help inform future pest control strategies.

5.
Front Physiol ; 14: 1130389, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37051022

RESUMO

Genes of the cytochrome P450 (CYP450) superfamily are known to be involved in the evolution of insecticide resistance. In this study, the transcriptomes of two Megalurothrips usitatus Bagnall (Thysanoptera: Thripidae) strains (resistant and susceptible) were screened for detoxification genes. MusiDN2722 encodes a protein composed of 504 amino acid residues with a relative molecular mass of 57.3 kDa. Multiple sequence alignment and phylogenetic analysis showed that MusiDN2722 is a member of the CYP450 family and has characteristics of the conserved CYP6 domain shared by typical CYP450 family members. RT-qPCR (real-time quantitative polymerase chain reaction) analysis showed that MusiDN2722 was upregulated in the acetamiprid-resistant strain compared with the susceptible strain (p < 0.05), and the relative expression level was significantly higher at 48 h after exposure than at 24 h after exposure. The interference efficiency of the injection method was higher than that of the membrane-feeding method. Silencing of MusiDN2722 through RNA interference significantly increased the sensitivity of M. usitatus to acetamiprid. Overall, this study revealed that MusiDN2722 plays a crucial role in the resistance of M. usitatus to acetamiprid. The findings will not only advance our understanding of the role of P450s in insecticide resistance but also provide a potential target for the sustainable control of destructive pests such as thrips.

6.
Enzyme Microb Technol ; 166: 110226, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36913860

RESUMO

Gastrodin, the major effective ingredient in Tianma (Gastrodia elata), is a p-hydroxybenzoic acid derivative with various activities. Gastrodin has been widely investigated for food and medical applications. The last biosynthetic step for gastrodin is UDP-glycosyltransferase (UGT)-mediated glycosylation with UDP-glucose (UDPG) as glycosyl donor. In this study, we performed a one-pot reaction both in vitro and in vivo to synthesize gastrodin from p-hydroxybenzyl alcohol (pHBA) by coupling UDP-glucosyltransferase from Indigofera tinctoria (itUGT2) to sucrose synthase from Glycine max (GmSuSy) for regeneration of UDPG. The in vitro results showed that itUGT2 transferred a glucosyl group to pHBA to generate gastrodin. After 37 UDPG regeneration cycles with 2.5% (molar ratio) UDP, the pHBA conversion reached 93% at 8 h. Furthermore, a recombinant strain with itUGT2 and GmSuSy genes was constructed. Through optimizing the incubation conditions, a 95% pHBA conversion rate (220 mg/L gastrodin titer) was achieved in vivo without addition of UDPG, which was 2.6-fold higher than that without GmSuSy. This in situ system for gastrodin biosynthesis provides a highly efficient strategy for both in vitro gastrodin synthesis and in vivo biosynthesis of gastrodin in E. coli with UDPG regeneration.


Assuntos
Glicosiltransferases , Uridina Difosfato Glucose , Glicosiltransferases/genética , Escherichia coli/genética , Glucose
7.
J Gen Appl Microbiol ; 68(3): 134-142, 2022 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-35965062

RESUMO

A xylanase gene xynZT-1 from Alteromonas macleodii HY35 was cloned and expressed in Escherichia coli (E. coli). The sequencing results showed that the ORF of xynZT-1 was 831 bp. The xylanase DNA sequence encoded a 29 amino acids (aa) signal peptide and a 247-aa mature peptide. The XynZT-1 has been a calculated molecular weight (MW) of 27.93 kDa, isoelectric point (pI) of 5.11 and the formula C1266H1829N327O384S5. The amino acid sequence of the xynZT-1 had a high similarity with that of glycosyl hydrolase family 11 (GHF11) reported from other microorganisms. The DNA sequence encoding mature peptide was subcloned into pET-28a(+) expression vector. The resulted plasmid pET-28a-xynZT-1 was transformed into E. coli BL21(DE3), and the recombinant strain BL21(DE3)/xynZT-1 was obtained. The optimum temperature and pH of the recombinant XynZT-1 were 45 ℃ and 5.0, respectively.


Assuntos
Escherichia coli , Peptídeos , Escherichia coli/genética , Escherichia coli/metabolismo , Clonagem Molecular , Estabilidade Enzimática , Peptídeos/genética , Peptídeos/metabolismo , Proteínas Recombinantes/metabolismo
8.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 30(1): 22-29, 2022 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-35123599

RESUMO

OBJECTIVE: To investigate the effect of monoammonium glycyrrhizinate on the stem cell-like characteristics, oxidative stress and mitochondrial function of acute promyelocytic leukemia cells NB4. METHODS: CCK-8 method was used to detect the viability of acute promyelocytic leukemia cells NB4, and the appropriate dose was screened; Cloning method was used to detect the proliferation rate of NB4 cell; Western blot was used to detect the expression of cell cycle-related protein; flow cytometry was used to detect cell apoptosis and sort NB4 stem cells positive (CD133+); Stem cell markers (Oct4, ABCG2, Dclk1) were detected by RT-PCR; ROS was detected by fluorescence; The kit was used to detect the level of oxidative stress markers (MDA); The flow cytometry was used to detect the change of mitochondrial membrane potential; Western blot was used to detect the expression of mitochondrial damage index-related proteins (Bax/BCL-2). RESULTS: Compared with the control group, if the concentration of MAG was less than 5 µmol/L, the cell NB4 viability showed no significant difference; if the concentration was higher than 5 µmol/L, the inhibitory effect on the growth of cell NB4 increased and showed significant difference (P<0.05), according to the results of CCK-8 experiment, four groups were set based on the concentration of MAG 0 µmol/L, MAG 5 µmol/L, MAG 10 µmol/L, and MAG 20 µmol/L; compared with the control group (MAG 0 µmol/L), the cells in MAG 5 µmol/L group showed no significant difference, while the proliferation rate, cyclin expression, mitochondrial membrane potential, stem cell CD133+ ratio, and marker mRNA level ( Oct4, ABCG2, Dclk1) of NB4 cell were significantly reduced (P<0.05); the apoptosis rate, reactive oxygen species, MDA content and Bax/BCL-2 expression of NB4 cell significantly increased (P<0.05). CONCLUSION: Monoammonium glycyrrhizinate has a significant inhibitory effect on acute promyelocytic leukemia cells NB4, which may be related to the regulation of stem cell-like characteristics, oxidative stress and mitochondrial function.


Assuntos
Leucemia Promielocítica Aguda , Apoptose , Linhagem Celular Tumoral , Quinases Semelhantes a Duplacortina , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Mitocôndrias , Estresse Oxidativo , Proteínas Serina-Treonina Quinases , Células-Tronco
9.
Enzyme Microb Technol ; 149: 109853, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34311890

RESUMO

Polyphosphate kinase (PPK) is important for industrial processes involving ATP regeneration. While a variety of methods have been reported for regenerating ATP from ADP, few have explored enzyme catalyzed ATP regeneration from cheaper and stable AMP. In this work, PPKs from different sources were expressed and their catalytic activity were tested at different reaction temperatures, reaction pH and with different polyphosphate (polyPn) types. The ATP regeneration system for glutathione (GSH) synthesis was established using a single PPK capable of phosphorylating AMP to synthesize ATP from AMP and short chain polyPn. GSH yield was obtained using adenosine mono-, di- and triphosphates, which confirmed the flexibility of our constructed ATP regeneration system coupled with GSH synthesis via bifunctional GSH synthase. Finally, optimization of the GSH synthesis yielded conversion value above 80 %. Overall, these results illustrate that PPK is suitable for a broader range of substrates than previously expected, and has great untapped potential for applications involving ATP regeneration.


Assuntos
Trifosfato de Adenosina , Polifosfatos , Monofosfato de Adenosina , Glutationa , Fosfotransferases (Aceptor do Grupo Fosfato) , Regeneração
10.
Microb Cell Fact ; 20(1): 38, 2021 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-33557849

RESUMO

BACKGROUND: Violaceins have attracted much attention as potential targets used in medicines, food additives, insecticides, cosmetics and textiles, but low productivity was the key factor to limit their large-scale applications. This work put forward a direct RBS engineering strategy to engineer the violacein biosynthetic gene cluster cloned from Chromobacterium violaceum ATCC 12,472 to efficiently improve the fermentation titers. RESULTS: Through four-rounds of engineering of the native RBSs within the violaceins biosynthetic operon vioABCDE, this work apparently broke through the rate-limiting steps of intermediates conversion, resulting in 2.41-fold improvement of violaceins production compared to the titers of the starting strain Escherichia coli BL21(DE3) (Vio12472). Furthermore, by optimizing the batch-fermentation parameters including temperature, concentration of IPTG inducer and fermentation time, the maximum yield of violaceins from (BCDE)m (tnaA-) reached 3269.7 µM at 2 mM tryptophan in the medium. Interestingly, rather than previous reported low temperature (20 ℃), we for the first time found the RBS engineered Escherichia coli strain (BCDE)m worked better at higher temperature (30 ℃ and 37 ℃), leading to a higher-level production of violaceins. CONCLUSIONS: To our knowledge, this is the first time that a direct RBS engineering strategy is used for the biosynthesis of natural products, having the potential for a greater improvement of the product yields within tryptophan hyperproducers and simultaneously avoiding the costly low temperature cultivation for large-scale industrial production of violaciens. This direct RBS engineering strategy could also be easily and helpfully used in engineering the native RBSs of other larger and value-added natural product biosynthetic gene clusters by widely used site-specific mutagenesis methods represented by inverse PCR or CRISPR-Cas9 techniques to increase their fermentation titers in the future.


Assuntos
Escherichia coli , Genes Bacterianos , Indóis/metabolismo , Engenharia Metabólica , Família Multigênica , Chromobacterium/enzimologia , Chromobacterium/genética , Escherichia coli/genética , Escherichia coli/metabolismo
11.
Health Data Sci ; 2021: 9806173, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-36405357

RESUMO

Background: Hundreds of coronavirus disease 2019 (COVID-19) clinical practice guidelines (CPGs) and expert consensus statements have been developed and published since the outbreak of the epidemic. However, these CPGs are of widely variable quality. So, this review is aimed at systematically evaluating the methodological and reporting qualities of COVID-19 CPGs, exploring factors that may influence their quality, and analyzing the change of recommendations in CPGs with evidence published. Methods: We searched five electronic databases and five websites from 1 January to 31 December 2020 to retrieve all COVID-19 CPGs. The assessment of the methodological and reporting qualities of CPGs was performed using the AGREE II instrument and RIGHT checklist. Recommendations and evidence used to make recommendations in the CPGs regarding some treatments for COVID-19 (remdesivir, glucocorticoids, hydroxychloroquine/chloroquine, interferon, and lopinavir-ritonavir) were also systematically assessed. And the statistical inference was performed to identify factors associated with the quality of CPGs. Results: We included a total of 92 COVID-19 CPGs developed by 19 countries. Overall, the RIGHT checklist reporting rate of COVID-19 CPGs was 33.0%, and the AGREE II domain score was 30.4%. The overall methodological and reporting qualities of COVID-19 CPGs gradually improved during the year 2020. Factors associated with high methodological and reporting qualities included the evidence-based development process, management of conflicts of interest, and use of established rating systems to assess the quality of evidence and strength of recommendations. The recommendations of only seven (7.6%) CPGs were informed by a systematic review of evidence, and these seven CPGs have relatively high methodological and reporting qualities, in which six of them fully meet the Institute of Medicine (IOM) criteria of guidelines. Besides, a rapid advice CPG developed by the World Health Organization (WHO) of the seven CPGs got the highest overall scores in methodological (72.8%) and reporting qualities (83.8%). Many CPGs covered the same clinical questions (it refers to the clinical questions on the effectiveness of treatments of remdesivir, glucocorticoids, hydroxychloroquine/chloroquine, interferon, and lopinavir-ritonavir in COVID-19 patients) and were published by different countries or organizations. Although randomized controlled trials and systematic reviews on the effectiveness of treatments of remdesivir, glucocorticoids, hydroxychloroquine/chloroquine, interferon, and lopinavir-ritonavir for patients with COVID-19 have been published, the recommendations on those treatments still varied greatly across COVID-19 CPGs published in different countries or regions, which may suggest that the CPGs do not make sufficient use of the latest evidence. Conclusions: Both the methodological and reporting qualities of COVID-19 CPGs increased over time, but there is still room for further improvement. The lack of effective use of available evidence and management of conflicts of interest were the main reasons for the low quality of the CPGs. The use of formal rating systems for the quality of evidence and strength of recommendations may help to improve the quality of CPGs in the context of the COVID-19 pandemic. During the pandemic, we suggest developing a living guideline of which recommendations are supported by a systematic review for it can facilitate the timely translation of the latest research findings to clinical practice. We also suggest that CPG developers should register the guidelines in a registration platform at the beginning for it can reduce duplication development of guidelines on the same clinical question, increase the transparency of the development process, and promote cooperation among guideline developers all over the world. Since the International Practice Guideline Registry Platform has been created, developers could register guidelines prospectively and internationally on this platform.

12.
Ann Transl Med ; 8(10): 627, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32566564

RESUMO

BACKGROUND: Glucocorticoids are widely used in the treatment of various pulmonary inflammatory diseases, but they are also often accompanied by significant adverse reactions. Published guidelines point out that low dose and short duration systemic glucocorticoid therapy may be considered for patients with rapidly progressing coronavirus disease 2019 (COVID-19) while the evidence is still limited. METHODS: We comprehensively searched electronic databases and supplemented the screening by conducting a manual search. We included randomized controlled trials (RCTs) and cohort studies evaluating the effectiveness and safety of glucocorticoids in children and adults with COVID-19, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), and conducted meta-analyses of the main indicators that were identified in the studies. RESULTS: Our search retrieved 23 studies, including one RCT and 22 cohort studies, with a total of 13,815 patients. In adults with COVID-19, the use of systemic glucocorticoid did not reduce mortality [risk ratio (RR) =2.00, 95% confidence interval (CI): 0.69 to 5.75, I2=90.9%] or the duration of lung inflammation [weighted mean difference (WMD) =-1 days, 95% CI: -2.91 to 0.91], while a significant reduction was found in the duration of fever (WMD =-3.23 days, 95% CI: -3.56 to -2.90). In patients with SARS, glucocorticoids also did not reduce the mortality (RR =1.52, 95% CI: 0.89 to 2.60, I2=84.6%), duration of fever (WMD =0.82 days, 95% CI: -2.88 to 4.52, I2=97.9%) or duration of lung inflammation absorption (WMD =0.95 days, 95% CI: -7.57 to 9.48, I2=94.6%). The use of systemic glucocorticoid therapy prolonged the duration of hospital stay in all patients (COVID-19, SARS and MERS). CONCLUSIONS: Glucocorticoid therapy was found to reduce the duration of fever, but not mortality, duration of hospitalization or lung inflammation absorption. Long-term use of high-dose glucocorticoids increased the risk of adverse reactions such as coinfections, so routine use of systemic glucocorticoids for patients with COVID-19 cannot be recommend.

13.
Int J Syst Evol Microbiol ; 70(1): 334-339, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31622234

RESUMO

A novel Gram-stain-negative, rod-shaped, non-spore-forming, non-flagellated, strictly aerobic strain, designated A6024T, was isolated from coastal seawater near Rizhao, PR China (119.61° E 35.47° N). The organism grew optimally at 28 °C, in pH 6.0-7.0 and in the presence of 3.0 % (w/v) NaCl. The strain required seawater or artificial seawater for growth and NaCl alone did not support growth. Strain A6024T contained ubiquinone 10 as the sole respiratory quinone and C18 : 1 ω7c (75.2 %) as the most abundant fatty acid. The predominant polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, one unidentified aminolipid and two unidentified lipids. The DNA G+C content of strain A6024T was 59.9 mol%. The results of phylogenetic analysis based on 16S rRNA gene sequences showed that the novel strain was related most closely to Aliiroseovarius halocynthiae MA1-10T, Aliiroseovarius pelagivivens GYSW-22T and Aliiroseovarius crassostreae CV919-312T with 98.3, 97.6 and 97.4 % sequence similarities, respectively. The calculated average nucleotide identity values and DNA-DNA hybridization values between strain A6024T and the phylogenetically related Aliiroseovarius species were in the range 76.0-85.6 % and 19.6-29.4 %, respectively. On the basis of the results of polyphasic analyses, strain A6024T represents a novel species of the genus Aliiroseovarius, for which the name Aliiroseovarius marinus sp. nov. is proposed. The type strain is A6024T (=KCTC 72114T=MCCC 1K03595T).


Assuntos
Filogenia , Rhodobacteraceae/classificação , Água do Mar/microbiologia , Microbiologia da Água , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Rhodobacteraceae/isolamento & purificação , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/química
14.
Int J Syst Evol Microbiol ; 69(12): 3857-3862, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31486761

RESUMO

A novel bacterial strain, C3212T, was isolated from a marine alga collected from the sea shore of Yantai, China. The strain was Gram-stain-negative, rod-shaped, aerobic, non-motile, and oxidase- and catalase-positive. Growth was observed at 8-37 °C (optimum, 28 °C), at pH 6.0-9.0 (optimum, pH 7.0) and in the presence of 1.0-7.0 % (w/v) NaCl (optimum, 4.0 %). The major respiratory quinone was ubiquinone-8 (Q-8). The polar lipids of strain C3212T consisted of diphosphatidylglycerol (cardiolipin), phosphatidylglycerol, phosphatidylethanolamine, an unidentified aminophospholipid, an unidentified phospholipid and an unidentified polar lipid. The major fatty acids were C16 : 1ω6c and/or C16 : 1ω7c, and C18 : 1ω6c and/or C18 : 1ω7c. The DNA G+C content of strain C3212T was 44.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that the novel strain was related most closely to Leucothrix pacifica XH122T, Leucothrix arctica IMCC 9719T and Leucothrix mucor DSM 2157T with similarities of 98.0, 97.5 and 94.3 %, respectively. Estimated DNA-DNA hybridization values were 14.2, 20.7 and 13.9 % between strain C3212T and L. pacifica XH122T, L. arctica IMCC 9719T and L. mucor DSM 2157T, respectively. Phenotypic, phylogenetic and genomic analyses revealed that strain C3212T represents a novel species of the genus Leucothrix, for which the name Leucothrix sargassi sp. nov. is proposed. The type strain is C3212T (=MCCC 1K03600T=KCTC 72121T).


Assuntos
Filogenia , Sargassum/microbiologia , Thiotrichaceae/classificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Thiotrichaceae/isolamento & purificação , Ubiquinona/química
15.
J Gen Appl Microbiol ; 65(5): 240-245, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-30905899

RESUMO

In this study, a mutant xylanase of high thermostability was obtained by site-directed mutagenesis. The homologous 3D structure of xylanase was successfully modeled and the mutation sites were predicted using bioinformatics software. Two amino acids of XynZF-2 were respectively substituted by cysteines (T205C and A52C) and a disulfide bridge was introduced into the C-terminal of XynZF-2. The mutant gene xynZFTA was cloned into pPIC9K and expressed in P. pastoris. The optimum temperature of the variant XynZFTA was improved from 45°C to 60°C, and XynZFTA retained greater than 90.0% activity (XynZF-2 retained only 50.0% activity) after treatment at 50°C for 5 min. The optimum pH of mutant xylanase was similar to XynZF-2 (pH = 5.0). The pH stability span (5.0~7.0) of the mutant xylanase was increased to 3.0~9.0. Overall, the results implied that the introduction of a disulfide bridge in the C-terminal structure improved the thermostability and pH stability of XynZF-2.


Assuntos
Aspergillus niger/enzimologia , Endo-1,4-beta-Xilanases/química , Proteínas Fúngicas/química , Aspergillus niger/genética , Domínio Catalítico , Cátions , Dissulfetos/química , Endo-1,4-beta-Xilanases/genética , Endo-1,4-beta-Xilanases/metabolismo , Estabilidade Enzimática , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Concentração de Íons de Hidrogênio , Modelos Moleculares , Mutagênese Sítio-Dirigida , Mutação , Pichia/genética , Pichia/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Temperatura
16.
Int J Syst Evol Microbiol ; 68(1): 271-276, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29143725

RESUMO

A novel Gram-stain-negative, straight or slightly curved rod-shaped, non-spore-forming, non-flagellated, strictly aerobic strain, designated RZG4-3-1T, was isolated from coastal seawater of Rizhao, China (119.625° E 35.517° N). The organism grew optimally at 24-28 °C, at pH 7.0 and in the presence of 2.0 % (w/v) NaCl. The strain required seawater or artificial seawater for growth, and NaCl alone did not support growth. Strain RZG4-3-1T contained ubiquinone 8 (Q-8) as the major respiratory quinone and contained C16 : 1ω7c and/or C16 : 1ω6c and C16 : 0 as the dominant fatty acids. The polar lipids of strain RZG4-3-1T were phosphatidylethanolamine, phosphatidylglycerol and one unidentified aminophospholipid. The DNA G+C content of strain RZG4-3-1T was 40.1 mol%. Strain RZG4-3-1T exhibited the highest 16S rRNA gene sequence similarity value (96.0 %) to Thalassotalea eurytherma JCM 18482T. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain RZG4-3-1T belonged to the genus Thalassotalea. On the basis of polyphasic analyses, strain RZG4-3-1T represents a novel species of the genus Thalassotalea, for which the name Thalassotalea atypica sp. nov. is proposed. The type strain is RZG4-3-1T (=JCM 31894T=KCTC 52745T=MCCC 1K03276T). An emended description of Thalassotalea eurytherma is also provided.


Assuntos
Gammaproteobacteria/classificação , Filogenia , Água do Mar/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Gammaproteobacteria/genética , Gammaproteobacteria/isolamento & purificação , Fosfatidiletanolaminas/química , Fosfatidilgliceróis/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/química
17.
Artif Cells Nanomed Biotechnol ; 45(6): 1-8, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27362580

RESUMO

Based on our previous work on the PLGA nanoparticles modified with biotinylated chitosan (Bio-CS-PLGA NPs), we further studied the stability, toxicity, pharmacokinetics, and in vivo efficacy. The safety of NPs was studied through single-dose toxicity test in mice, and the result showed that NPs were well tolerated at the dose of 300 mg/kg. Compared with the free EPB group, the NPs group exhibited higher plasma drug concentration, longer half-life time. EPB-loaded NPs significantly inhibited the tumor growth compared to free EPB. All results suggested that Bio-CS-PLGA NPs were stable, safe, and showed a promising potential on targeted drug delivery.


Assuntos
Quitosana , Sistemas de Liberação de Medicamentos/métodos , Ácido Láctico , Neoplasias Experimentais/tratamento farmacológico , Ácido Poliglicólico , Animais , Biotinilação , Quitosana/efeitos adversos , Quitosana/farmacocinética , Quitosana/farmacologia , Feminino , Ácido Láctico/efeitos adversos , Ácido Láctico/farmacocinética , Ácido Láctico/farmacologia , Camundongos , Ácido Poliglicólico/efeitos adversos , Ácido Poliglicólico/farmacocinética , Ácido Poliglicólico/farmacologia , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Ratos , Ratos Wistar
18.
Oncotarget ; 7(49): 81377-81388, 2016 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-27835608

RESUMO

The androgen receptor (AR) is not only a ligand-dependent transcription factor, but also functions as a licensing factor, a component of DNA replication, which is degraded during mitosis. Furthermore, the deregulation of AR activity is involved in the initiation of prostate cancer and contributes to castration resistant prostate cancer (CRPC). While AR degradation is known to occur primarily through a proteasome-mediated pathway, very little is known about how this process is regulated, especially in M phase. PC-1 is an androgen-responsive factor and expresses specificity in prostate cancer, with higher expression noted at G2/M. In this study, PC-1 was shown to interact with AR and E3 ligase CHIP (Carboxy-terminus of Hsc70 Interacting Protein) and to enhance AR/CHIP interactions, thereby decreasing AR stability. Moreover, PC-1 was found to act in conjunction with CHIP in the decreasing of AR via ubiquitination, with the subsequent degradation predominantly occurring during M phase. PC-1 was also found to repress AR transcriptional activity in androgen-dependent and androgen-independent prostate cancer cells and attenuate the growth inhibition of AR. In conclusion, these findings should provide new clues regarding the modulation of AR turnover and activity via PC-1 and reveals an essential role of PC-1 in AR signaling.


Assuntos
Diester Fosfórico Hidrolases/metabolismo , Neoplasias de Próstata Resistentes à Castração/enzimologia , Pirofosfatases/metabolismo , Receptores Androgênicos/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Pontos de Checagem do Ciclo Celular , Linhagem Celular Tumoral , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Humanos , Masculino , Diester Fosfórico Hidrolases/genética , Neoplasias de Próstata Resistentes à Castração/genética , Neoplasias de Próstata Resistentes à Castração/patologia , Estabilidade Proteica , Proteólise , Pirofosfatases/genética , Receptores Androgênicos/genética , Transdução de Sinais , Fatores de Tempo , Transcrição Gênica , Transfecção , Ubiquitinação
19.
Angew Chem Int Ed Engl ; 55(47): 14693-14697, 2016 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-27712024

RESUMO

Highly crystalline graphitic carbon nitride (g-C3 N4 ) with decreased structural imperfections benefits from the suppression of electron-hole recombination, which enhances its hydrogen generation activity. However, producing such g-C3 N4 materials by conventional heating in an electric furnace has proven challenging. Herein, we report on the synthesis of high-quality g-C3 N4 with reduced structural defects by judiciously combining the implementation of melamine-cyanuric acid (MCA) supramolecular aggregates and microwave-assisted thermolysis. The g-C3 N4 material produced after optimizing the microwave reaction time can effectively generate H2 under visible-light irradiation. The highest H2 evolution rate achieved was 40.5 µmol h-1 , which is two times higher than that of a g-C3 N4 sample prepared by thermal polycondensation of the same supramolecular aggregates in an electric furnace. The microwave-assisted thermolysis strategy is simple, rapid, and robust, thereby providing a promising route for the synthesis of high-efficiency g-C3 N4 photocatalysts.

20.
J Pediatr Hematol Oncol ; 38(6): 437-42, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27322718

RESUMO

A survey of the clinical data on acute myeloid leukemia (AML) over the past 10 years in the treatment center of Children's Hospital was presented. The aim of the study was to identify the factors influencing the treatment abandonment rate (AR) of AML. Of the 474 AML cases examined, 264 were abandoned (55.7%). The most important factor affecting AR appeared to be the AML subtype-that is, the M3 versus non-M3 (42% vs. 60%). Patient age was observed to be closely related to AR-the older the patients, the lower the AR-and infants had the highest prevalence of abandonment (84.2%). The patient's residential location was markedly correlated to AR, which was almost inversely proportional to the size of the township where the patient came from. From large cities, intermediate and small towns to countryside villages, the AR increased linearly. So was the correlation with health insurance coverage, which decreased in the same way. Sex and karyotypes did not affect AR. In conclusion, the patients' financial burden and the perceived incurability of AML were the 2 leading factors dominating the decision for abandonment in parents and caregivers.


Assuntos
Leucemia Mieloide Aguda/terapia , Adolescente , Criança , Pré-Escolar , Feminino , Seguimentos , Custos de Cuidados de Saúde , Humanos , Lactente , Recém-Nascido , Seguro Saúde , Cariótipo , Masculino , Resultado do Tratamento , Recusa do Paciente ao Tratamento
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA