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1.
J Craniofac Surg ; 34(5): 1570-1574, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36879388

RESUMEN

BACKGROUND: With the growing popularity of rejuvenation, people are giving more concerns on their temporal depression which makes them look older and wishing to improve it by injection. The complex structure of the temporal region leads to a higher risk of failed injection. The temporal region is well understood based on cadaver anatomy, but few studies have described its spatial structure. The purpose of this study was to improve the efficacy and safety of temporal injection by studying the spatial structure of the soft tissues and major blood vessels in each layer of the temporal region. METHODS: A total of 30 volunteers (24 men and 6 women, 60 temporal regions) were investigated. Color Doppler ultrasound was used to measure the thickness of the temporal layers at the selected measurement points (A, B, C, D, E, and F). The maximum thickness of the temporal fat pads was also measured, and the layers, depths and diameters of the major temporal vessels (frontal branch of superficial temporal artery and vein, middle temporal vein and deep temporal artery) were measured. RESULTS: At the various measurement points, the thickness and position of the skin, subcutaneous fat superficial fascia, and temporalis muscle did not differ significantly, whereas the superficial temporal fat pad and deep temporal fat pad differed significantly. The diameter and depth of the superficial temporal artery, superficial temporal vein, and deep temporal artery did not differ significantly, whereas the diameter of the middle temporal vein differed slightly, whereas the depth differed more obviously. CONCLUSIONS: The temporal structure is very complex, and understanding the spatial position of each layer of tissue plays an important role in improving the efficacy and safety of temporal filler injection. Ultrasound can help us to understand this information and assist in therapy. LEVEL OF EVIDENCE: Level II.


Asunto(s)
Fascia , Tejido Subcutáneo , Masculino , Humanos , Femenino , Fascia/anatomía & histología , Grasa Subcutánea , Tejido Adiposo/anatomía & histología , Músculo Temporal/anatomía & histología , Cadáver , Lóbulo Temporal
2.
Front Oncol ; 13: 1111985, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36776342

RESUMEN

Background: Currently, malignant peripheral nerve sheath tumors (MPNST) are the subject of intense research interest. However, bibliometric studies have not been conducted in this field. The purpose of the study was to identify historical trends and presents a bibliometric analysis of the MPNST literature from 2000 to 2022. Methods: For the bibliometric analysis, publications were retrieved from the Web of Science database based on the following search terms: [TI = (MPNST) OR TI= (malignant peripheral nerve sheath tumors) AND PY = (2000-2022)]. The following information was collected for each document: the publication trends and geographical distribution, important authors and collaboration, keyword distribution and evaluation, most popular journals, and most influential articles. Results: We included 1400 documents for bibliometric analysis, covering five categories: 824 articles, 17 proceedings papers, 68 letters, 402 meeting abstracts, and 89 reviews. Corrections, editorials, book chapters, data papers, publications with expressed concerns, and retractions were excluded from our research. Conclusion: Since 2000, the number of publications on MPNST has continuously increased. Among all countries that contributed to the MPNST research, the USA, Japan, and China were the three most productive countries. The journal Modern Pathology has the most publications on MPNST, while those in the Cancer Research journal were the most frequently cited. The University of Texas MD Anderson Cancer Center may be a good partner to collaborate with. Recent research trends in MPNST have focused on tumorigenesis, clinical management, and predictive biomarkers.

3.
Educ Stud Math ; 112(1): 103-121, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-35937038

RESUMEN

Due to the COVID-19 pandemic in Shanghai, China, all school classes were delivered through an online environment from February 24 to May 22, 2020. To support this transition, the Shanghai Education Commission led expert teachers and specialists to develop a series of online video lessons based on the Shanghai unified curriculum, and suggested students watch the online video lessons individually from home, followed by an online synchronous lesson supported by class teachers. This study investigated what primary mathematics teachers learned from addressing these challenges through a case study. By following two purposefully selected teachers over 2 weeks during the transition, multiple data sets including online video lessons, online synchronous lessons, daily reflections, and post-online teacher interviews were collected. A fine-grained analysis of the data from the lens of the documentational approach to didactics found that teachers adaptively used online video lessons as important resources for their online synchronous lessons and virtual Teaching Research Groups as a teachers' collaboration mechanism supported them to develop online video lessons and address various technological constraints. Finally, implications of this case study for mathematics education globally are discussed. Supplementary Information: The online version contains supplementary material available at 10.1007/s10649-022-10172-2.

4.
ZDM ; 54(2): 359-372, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35669530

RESUMEN

In the research reported in this paper we investigated teachers' changes when adopting and adapting to emergency online teaching during the COVID-19 pandemic, from the perspective of the Interconnected Model of Professional Growth (IMPG). By adapting complementary accounts methodology to research into teachers' changes when addressing the unexpected migration to online teaching, an integrated data set, including online teaching videos, teacher daily reflections, and teacher interviews from two purposefully selected teachers over two weeks of online teaching, was collected and analyzed qualitatively. Both teachers encountered different difficulties and thus had different knowledge changes displayed in different change routes. For the experienced teacher, students' mistakes in homework and her online teaching practice triggered her knowledge changes. For the young teacher, the online video lessons, relevant resources on the Internet and students' performance were her primary sources that triggered the changes of her knowledge for teaching. These differences between the experienced teacher and young teacher provide evidence of the complexity of teacher's professional growth, which is related to a variety of external and internal factors. This study demonstrates how the IMPG model helps uncover teachers' changes in such an unprecedented virtual-teaching environment. Finally, the implications of this study for teacher professional development in general are discussed. Supplementary Information: The online version contains supplementary material available at 10.1007/s11858-022-01378-y.

5.
PeerJ ; 10: e12588, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35702258

RESUMEN

Background: Previous studies have been reported the immune dysfunction of various live tissues. However, the potential molecular mechanism of post-transcriptional regulation of immune related genes in hepatocellular carcinoma (HCC) is still not clear. We tried to identify crucial immune related biomarkers associated with HCC patients' outcomes and to reveal the transcriptional regulation. Method: The fractions of 22 immune cells in tumor and adjacent tissues were estimated by CIBERSORT. Kruskal-Wallis test and differentially expressed analyzes were used for comparative studies. Cox proportional hazard regression model, Kaplan-Meier estimates and Log-rank test were used for survival analyses. Results: From The Cancer Genome Atlas (TCGA), the gene, lncRNA and miRNA expression profiles of 379 HCC samples with clinical information were used for comparative studies. Eleven adaptive and innate immune cell types were significantly altered in HCC samples, including B cell memory, regulatory T cells and follicular helper T cells. Differentially expressed competing endogenous RNA (ceRNA) network associated with patients' overall survival was identified. Then, the novel pathway, including LINC00261, MiR105-5p and selectin L(SELL) was found and may be potential novel biomarkers for patients' outcomes and immunotherapy. Furthermore, SELL was significantly positively correlated (correlation coefficients: 0.47-0.69) with 12 known gene signatures of immunotherapy except for programmed cell death 1 (PDCD1). Conclusions: Our findings could provide insights into the selection of novel LINC00261/MiR105-5p/SELL pathway which is associated with overall survival and may impact on efficacy of immunotherapy in HCC.


Asunto(s)
Carcinoma Hepatocelular , Selectina L , Neoplasias Hepáticas , MicroARNs , ARN Largo no Codificante , Humanos , Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , MicroARNs/genética , Modelos de Riesgos Proporcionales , ARN Largo no Codificante/genética , Selectina L/genética , Linfocitos B
6.
Front Oncol ; 12: 891917, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35600407

RESUMEN

Cell-free DNA (cfDNA) exists in various types of bodily fluids, including plasma, urine, bile, and others. Bile cfDNA could serve as a promising liquid biopsy for biliary tract cancer (BTC) patients, as bile directly contacts tumors in the biliary tract system. However, there is no commercial kit or widely acknowledged method for bile cfDNA extraction. In this study, we established a silica-membrane-based method, namely 3D-BCF, for bile cfDNA isolation, exhibiting effective recovery of DNA fragments in the spike-in assay. We then compared the 3D-BCF method with four other commercial kits: the BIOG cfDNA Easy Kit (BIOG), QIAamp DNA Mini Kit (Qiagen), MagMAXTM Cell-Free DNA Isolation Kit (Thermo Fisher), and NORGEN Urine Cell-Free Circulating DNA Purification Mini Kit (Norgen Biotek). The proposed 3D-BCF method exhibited the highest cfDNA isolation efficiency (p < 0.0001) from patient bile samples, and bile cfDNA of short, medium or long fragments could all be extracted effectively. To test whether the extracted bile cfDNA from patients carries tumor-related genomic information, we performed next-generation sequencing on the cfDNA and verified the gene-mutation results by polymerase chain reaction (PCR)-Sanger chromatograms and copy-number-variation (CNV) detection by fluorescence in situ hybridization (FISH) of tumor tissues. The 3D-BCF method could efficiently extract cfDNA from bile samples, providing technical support for bile cfDNA as a promising liquid biopsy for BTC patient diagnosis and prognosis.

7.
Immunopharmacol Immunotoxicol ; 44(4): 541-547, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35451929

RESUMEN

Background: The overall survival of melanoma patients remains poor despite advancements in surgical treatment and targeted therapies. Therefore, there is a need to develop new therapeutic strategies for melanoma. 2-methoxyestradiol (2-ME) is a major metabolite of estrogen that has been shown to have anti-tumor effects against many malignancies. However, the effects and mechanisms of action of 2-ME against melanoma remain unclear.Materials and methods: Melanoma cells (B16) were treated with 2-ME in vitro. Cell proliferation was detected by CCK8 and clone formation, transwell was carried out to measure the migration of B16 cells with or without 2-ME. Flow cytometry was performed to measure the apoptosis and cell cycle. C57BL/6 mice were used for tumor-bearing of B16 cells, tumor volumes were measured once a day, and sacrificed after it was over 2000 mm3, then immunofluorescence was implemented to examine the marker of CD3, CD8 and PD-L1.Results: In our study, we found that 2-ME significantly affected the proliferation, migration, apoptosis, and cell cycle of melanoma in vitro. Our results also showed that 2-ME had strong anti-tumor effects against melanoma in vivo and increased the infiltration of tumor-specific cytotoxic lymphocytes CD8+ T cells in the tumor microenvironment. Besides, PD-L1 expression in tumor cells was significantly higher in the 2-ME-treated group than in the control group, indicating that 2-ME could exhibit stronger anti-tumor effects against melanoma if combined with PD-1 blockade therapy.Conclusion: 2-ME suppresses melanoma in vivo and in vitro and is a promising synergistic enhancer of PD-1 blockade immunotherapy.


Asunto(s)
2-Metoxiestradiol , Inmunidad Adaptativa , Melanoma Experimental , 2-Metoxiestradiol/farmacología , 2-Metoxiestradiol/uso terapéutico , Animales , Antígeno B7-H1/metabolismo , Linfocitos T CD8-positivos , Ciclo Celular , Proliferación Celular , Inmunoterapia/métodos , Melanoma Experimental/tratamiento farmacológico , Melanoma Experimental/inmunología , Ratones , Ratones Endogámicos C57BL , Receptor de Muerte Celular Programada 1/metabolismo , Microambiente Tumoral
8.
Eng Life Sci ; 22(3-4): 119-131, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-35382533

RESUMEN

The conversion of carbohydrates in biomass via fermentation is an important component of an overall strategy to decarbonize the production of fuels and chemicals. Owing to the cost and resources required to produce biomass hydrolysates, the economic and environmental sustainability of these fermentation processes requires that they operate with high yields, sugar conversion, and productivity. Immobilized-cell technology in a continuous bioprocess can achieve significantly higher volumetric productivities than is possible from standard batch fermentation using free cells. Here, we demonstrate approaches for improvement of ethanol yield from algal hydrolysates and a mock hydrolysate medium. Saccharomyces cerevisiae was immobilized in alginate and incorporated into a two-column immobilized cell reactor system. Furthermore, the yeast quorum-sensing molecule, 2-phenylethanol, was added to improve ethanol yield by restricting growth and diverting sugar to ethanol. The bioreactor system could achieve high ethanol volumetric productivity (>20 g/Lreactor·h) and high glucose conversion (>99%) in mock hydrolysate, while the addition of 0.2% 2-phenylethanol resulted in 4.9% higher ethanol yield. With an algal hydrolysate of <10 g/L sugar, the ethanol volumetric productivity reached 9.8 g/Lreactor·h, and the addition of 0.2% 2-phenylethanol increased the ethanol yield by up to 7.4%. These results demonstrate the feasibility of novel strategies to achieve sustainability goals in biomass conversions.

9.
FEMS Yeast Res ; 21(8)2021 12 15.
Artículo en Inglés | MEDLINE | ID: mdl-34755845

RESUMEN

One strategy to increase the yield of desired fermentation products is to redirect substrate carbon from biomass synthesis. Nongenetic approaches to alter metabolism may have advantages of general applicability and simple control. The goal of this study was to identify and evaluate chemicals for their ability to inhibit the growth of Saccharomyces cerevisiae while allowing ethanol production with higher yields. Eight potential growth-inhibitory chemicals were screened for their ability to reduce cell growth in 24-well plates. Effective chemicals were then evaluated in cultivations to identify those that simultaneously reduced biomass yield and increased ethanol yield. The yeast quorum-sensing molecules 2-phenylethanol, tryptophol and tyrosol were found to increase the ethanol yield of S. cerevisiae JAY 270. These molecules were tested with seven other yeast strains and ethanol yields of up to 15% higher were observed. The effects of 2-phenylethanol and tryptophol were also studied in bioreactor fermentations. These findings demonstrate for the first time that the ethanol yield can be improved by adding yeast quorum-sensing molecules to reduce the cell growth of S. cerevisiae, suggesting a strategy to improve the yield of ethanol and other yeast fermentation products by manipulating native biological control systems.


Asunto(s)
Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Etanol , Fermentación , Percepción de Quorum , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo
10.
Microb Biotechnol ; 11(6): 1195-1206, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-30221488

RESUMEN

Plants can re-programme their transcriptome, proteome and metabolome to deal with environmental and biotic stress. It has been shown that the rhizosphere microbiome has influence on the plant metabolome and on herbivore behaviour. In the present study, Trichoderma gamsii was isolated from Arabidopsis thaliana rhizosphere soil. The inoculation of roots of Arabidopsis thaliana with T. gamsii significantly inhibited the feeding behaviour of Trichoplusia ni and affected the metabolome as well as the content of phytohormones in Arabidopsis leaves. T. gamsii-treated plant leaves had higher levels of amino acids and lower concentrations of sugars. In addition, T. gamsii-treated plant leaves had more abscisic acid (ABA) and lower levels of salicylic acid (SA) and indole-3-acetic acid (IAA) in comparison with the untreated plants. Furthermore, the inoculation with T. gamsii on different signalling mutants showed that the induction of defences were SA-dependent. These findings indicate that T. gamsii has potential as a new type of biocontrol agent to promote plant repellence to insect attacks.


Asunto(s)
Arabidopsis/microbiología , Herbivoria/fisiología , Mariposas Nocturnas/fisiología , Reguladores del Crecimiento de las Plantas/metabolismo , Hojas de la Planta/metabolismo , Trichoderma/fisiología , Ácido Abscísico/análisis , Ácido Abscísico/metabolismo , Animales , Arabidopsis/metabolismo , Arabidopsis/parasitología , Conducta Alimentaria , Ácidos Indolacéticos/análisis , Ácidos Indolacéticos/metabolismo , Metaboloma , Enfermedades de las Plantas/parasitología , Hojas de la Planta/microbiología , Hojas de la Planta/parasitología , Ácido Salicílico/análisis , Ácido Salicílico/metabolismo
11.
BMC Biotechnol ; 17(1): 86, 2017 12 04.
Artículo en Inglés | MEDLINE | ID: mdl-29202734

RESUMEN

BACKGROUND: Starch-binding domains from carbohydrate binding module family 20 have been used as a tool for starch engineering. Previous studies showed that expression of starch binding domain fusion proteins in planta resulted in modified starch granule structures and physicochemical properties. However, although 13 carbohydrate binding module families have been reported to contain starch-binding domains, only starch-binding domains from carbohydrate binding module family 20 have been well studied and introduced into plants successfully. In this study, two fragments, the tandem CBM25 domain and the tandem CBM25 with multiple fibronectin type III (FN3) domains of the α-amylase enzyme from Microbacterium aurum, were expressed in the tubers of a wild type potato cultivar (cv. Kardal) and an amylose-free (amf) potato mutant. RESULTS: The (CBM25)2 and FN3 protein were successfully accumulated in the starch granules of both Kardal and amf transformants. The accumulation of (CBM25)2 protein did not result in starch morphological alterations in Kardal but gave rise to rough starch granules in amf, while the FN3 resulted in morphological changes of starch granules (helical starch granules in Kardal and rough surface granules in amf) but only at a very low frequency. The starches of the different transformants did not show significant differences in starch size distribution, apparent amylose content, and physico-chemical properties in comparison to that of untransformed controls. CONCLUSION: These results suggest that the starch-binding domains from carbohydrate binding module family 25 can be used as a novel tool for targeting proteins to starch granules during starch biosynthesis without side-effects on starch morphology, composition and properties.


Asunto(s)
Ingeniería Metabólica/métodos , Plantas Modificadas Genéticamente/genética , Proteínas Recombinantes de Fusión/metabolismo , Solanum tuberosum/genética , Almidón/metabolismo , alfa-Amilasas/genética , Actinobacteria/enzimología , Actinobacteria/genética , Proteínas Bacterianas/genética , Sitios de Unión/genética , Fibronectinas , Plantas Modificadas Genéticamente/metabolismo , Dominios Proteicos/genética , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/genética , Solanum tuberosum/metabolismo , Almidón/química
12.
PLoS One ; 12(1): e0169610, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28056069

RESUMEN

Phosphate esters are responsible for valuable and unique functionalities of starch for industrial applications. Also in the cell phosphate esters play a role in starch metabolism, which so far has not been well characterized in storage starch. Laforin, a human enzyme composed of a carbohydrate-binding module and a dual-specificity phosphatase domain, is involved in the dephosphorylation of glycogen. To modify phosphate content and better understand starch (de)phosphorylation in storage starch, laforin was engineered and introduced into potato (cultivar Kardal). Interestingly, expression of an (engineered) laforin in potato resulted in significantly higher phosphate content of starch, and this result was confirmed in amylose-free potato genetic background (amf). Modified starches exhibited altered granule morphology and size compared to the control. About 20-30% of the transgenic lines of each series showed red-staining granules upon incubation with iodine, and contained higher phosphate content than the blue-stained starch granules. Moreover, low amylose content and altered gelatinization properties were observed in these red-stained starches. Principle component and correlation analysis disclosed a complex correlation between starch composition and starch physico-chemical properties. Ultimately, the expression level of endogenous genes involved in starch metabolism was analysed, revealing a compensatory response to the decrease of phosphate content in potato starch. This study provides a new perspective for engineering starch phosphate content in planta by making use of the compensatory mechanism in the plant itself.


Asunto(s)
Fosfatos/metabolismo , Plantas Modificadas Genéticamente/metabolismo , Solanum tuberosum/metabolismo , Almidón/metabolismo , Amilosa/metabolismo , Mutación/genética , Fosforilación , Plantas Modificadas Genéticamente/enzimología , Plantas Modificadas Genéticamente/genética , Proteínas Tirosina Fosfatasas no Receptoras/genética , Proteínas Tirosina Fosfatasas no Receptoras/metabolismo , Solanum tuberosum/enzimología , Solanum tuberosum/genética
13.
Carbohydr Polym ; 157: 1628-1637, 2017 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-27987877

RESUMEN

Starch phosphate esters are crucial in starch metabolism and render valuable functionality to starches for various industrial applications. A potato glucan, water dikinase (GWD1) was introduced in tubers of two different potato genetic backgrounds: an amylose-containing line Kardal and the amylose-free mutant amf. In both backgrounds, this resulted in two contrasting effects, a number of plants showed higher phosphate content compared to the respective control, while others lines exhibited lower phosphate content, thereby generating two series of starches with broad-scale variation in phosphate content. The results of systematic analyses on these two series of starches revealed that starch phosphate content strongly influenced starch granule morphology, amylose content, starch fine structure, gelatinization characteristics and freeze-thaw stability of starch gels. Further analyses on the expression level of genes involved in starch metabolism suggested that starch phosphorylation regulates starch synthesis by controlling the carbon flux into starch while simultaneously modulating starch-synthesizing genes.


Asunto(s)
Amilosa/química , Solanum tuberosum/química , Almidón/biosíntesis , Fosforilación
14.
Microb Ecol ; 72(3): 497-502, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-27338261

RESUMEN

Although it is well known that diet is one of the major modulators of the gut microbiome, how the major components of diet shape the gut microbial community is not well understood. Here, we developed a simple system that allows the investigation of the impact of given compounds as supplements of the diet on the termite gut microbiome. The 16S rRNA pyrosequencing analysis revealed that feeding termites different blends of sugars and amino acids did not majorly impact gut community composition; however, ingestion of blends of secondary metabolites caused shifts in gut bacterial community composition. The supplementation of sugars and amino acids reduced the richness significantly, and sugars alone increased the evenness of the gut bacterial community significantly. Secondary metabolites created the most dramatic effects on the microbial community, potentially overriding the effect of other types of compounds. Furthermore, some microbial groups were stimulated specifically by particular groups of compounds. For instance, termites fed with secondary metabolites contained more Firmicutes and Spirochaetes compared to the other treatments. In conclusion, our results suggest that the termite (Reticulitermes flavipes) can be used as a simple and effective system to test the effects of particular chemical compounds in modulating the gut microbiome.


Asunto(s)
Aminoácidos/metabolismo , Bacterias/clasificación , Metabolismo de los Hidratos de Carbono , Suplementos Dietéticos , Tracto Gastrointestinal/microbiología , Isópteros/metabolismo , Isópteros/microbiología , Metabolismo Secundario , Alimentación Animal/análisis , Animales , Bacterias/genética , Secuencia de Bases , Biodiversidad , ADN Bacteriano/genética , Dieta , Conducta Alimentaria , Tracto Gastrointestinal/metabolismo , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Spirochaeta/genética
15.
Planta ; 240(2): 409-21, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24893853

RESUMEN

MAIN CONCLUSION: Expression of amylosucrase in potato resulted in larger starch granules with rough surfaces and novel physico-chemical properties, including improved freeze-thaw stability, higher end viscosity, and better enzymatic digestibility. Starch is a very important carbohydrate in many food and non-food applications. In planta modification of starch by genetic engineering has significant economic and environmental benefits as it makes the chemical or physical post-harvest modification obsolete. An amylosucrase from Neisseria polysaccharea fused to a starch-binding domain (SBD) was introduced in two potato genetic backgrounds to synthesize starch granules with altered composition, and thereby to broaden starch applications. Expression of SBD-amylosucrase fusion protein in the amylose-containing potato resulted in starch granules with a rough surface, a twofold increase in median granule size, and altered physico-chemical properties including improved freeze-thaw stability, higher end viscosity, and better enzymatic digestibility. These effects are possibly a result of the physical interaction between amylosucrase and starch granules. The modified larger starches not only have great benefit to the potato starch industry by reducing losses during starch isolation, but also have an advantage in many food applications such as frozen food due to its extremely high freeze-thaw stability.


Asunto(s)
Glucosiltransferasas/metabolismo , Solanum tuberosum/metabolismo , Almidón/metabolismo , Glucosiltransferasas/genética , Solanum tuberosum/genética
16.
Microb Ecol ; 65(3): 531-6, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23529653

RESUMEN

Diets shape the animal gut microbiota, although the relationships between diets and the structure of the gut microbial community are not yet well understood. The gut bacterial communities of Reticulitermes flavipes termites fed on four individual plant biomasses with different degrees of recalcitrance to biodegradation were investigated by 16S rRNA pyrosequencing analysis. The termite gut bacterial communities could be differentiated between grassy and woody diets, and among grassy diets (corn stover vs. sorghum). The majority of bacterial taxa were shared across all diets, but each diet significantly enriched some taxa. Interestingly, the diet of corn stover reduced gut bacterial richness and diversity compared to other diets, and this may be related to the lower recalcitrance of this biomass to degradation.


Asunto(s)
Alimentación Animal/análisis , Bacterias/aislamiento & purificación , Biodiversidad , Isópteros/metabolismo , Isópteros/microbiología , Plantas/metabolismo , Madera/metabolismo , Animales , Bacterias/clasificación , Bacterias/genética , ADN Bacteriano/genética , Tracto Gastrointestinal/metabolismo , Tracto Gastrointestinal/microbiología , Datos de Secuencia Molecular , ARN Ribosómico 16S/genética
17.
Biotechnol Bioeng ; 110(6): 1616-26, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23297115

RESUMEN

The deconstruction of lignin to enhance the release of fermentable sugars from plant cell walls presents a challenge for biofuels production from lignocellulosic biomass. The discovery of novel lignin-degrading enzymes from bacteria could provide advantages over fungal enzymes in terms of their production and relative ease of protein engineering. In this study, 140 bacterial strains isolated from soils of a biodiversity-rich rainforest in Peru were screened based on their oxidative activity on ABTS, a laccase substrate. Strain C6 (Bacillus pumilus) and strain B7 (Bacillus atrophaeus) were selected for their high laccase activity and identified by 16S rDNA analysis. Strains B7 and C6 degraded fragments of Kraft lignin and the lignin model dimer guaiacylglycerol-ß-guaiacyl ether, the most abundant linkage in lignin. Finally, LC-MS analysis of incubations of strains B7 and C6 with poplar biomass in rich and minimal media revealed that a higher number of compounds were released in the minimal medium than in the rich one. These findings provide important evidence that bacterial enzymes can degrade and/or modify lignin and contribute to the release of fermentable sugars from lignocellulose.


Asunto(s)
Bacterias/enzimología , Bacterias/aislamiento & purificación , Ecosistema , Lignina/metabolismo , Microbiología del Suelo , Bacterias/genética , Bacterias/metabolismo , Proteínas Bacterianas/genética , Biocombustibles , Biomasa , ADN Bacteriano/análisis , ADN Bacteriano/genética , Lacasa/genética , Lignina/análisis , Lignina/química , Perú , Populus , ARN Ribosómico 16S/genética , Árboles
18.
Plant Biotechnol J ; 11(4): 470-9, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23231535

RESUMEN

The Escherichia coli glycogen branching enzyme (GLGB) was fused to either the C- or N-terminus of a starch-binding domain (SBD) and expressed in two potato genetic backgrounds: the amylose-free mutant (amf) and an amylose-containing line (Kardal). Regardless of background or construct used, a large amount of GLGB/SBD fusion protein was accumulated inside the starch granules, however, without an increase in branching. The presence of GLGB/SBD fusion proteins resulted in altered morphology of the starch granules in both genetic backgrounds. In the amf genetic background, the starch granules showed both amalgamated granules and porous starch granules, whereas in Kardal background, the starch granules showed an irregular rough surface. The altered starch granules in both amf and Kardal backgrounds were visible from the initial stage of potato tuber development. High-throughput transcriptomic analysis showed that expression of GLGB/SBD fusion protein in potato tubers did not affect the expression level of most genes directly involved in the starch biosynthesis except for the up-regulation of a beta-amylase gene in Kardal background. The beta-amylase protein could be responsible for the degradation of the extra branches potentially introduced by GLGB.


Asunto(s)
Enzima Ramificadora de 1,4-alfa-Glucano/metabolismo , Plantas Modificadas Genéticamente/metabolismo , Solanum tuberosum/metabolismo , Almidón/metabolismo , Enzima Ramificadora de 1,4-alfa-Glucano/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Plantas Modificadas Genéticamente/genética , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Solanum tuberosum/genética
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