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1.
Geriatr Gerontol Int ; 24(4): 415-420, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38445411

RESUMEN

AIM: The aim of this clinical study was to explore the effects of thumb-tack needling combined with sporting (TTNS) therapy on the improvement of pain and joint function in older adult patients with knee osteoarthritis (KOA). METHODS: A total of 120 older adult patients with KOA were randomly assigned to receive TTNS therapy or medicine treatment (Med group) only for 1 month. The patients were followed up for 3 months and clinical efficacies were evaluated using a visual analog scale to assess pain, the Lequesne scoring system to assess motor function, and the Western Ontario and McMaster University Osteoarthritis Index to assess KOA severity. Blood was collected to measure the levels of interleukin-6 and tumor necrotic factor-alpha using enzyme-linked immunosorbent assay. RESULTS: The data suggested that TTNS therapy resulted in a significantly higher clinical efficacy (P = 0.012). Visual analog scale score, Lequesne index, and Western Ontario and McMaster University Osteoarthritis Index of the TTNS group at the time of post-treatment (1 month) and post-follow-up (3 months) were also lower compared with the Med group. Patients in the TTNS group also showed lower levels of serum tumor necrotic factor-alpha and interleukin-6. CONCLUSIONS: TTNS therapy is more efficacious than pharmacological treatment in improving the clinical outcomes of patients with KOA, which suggests its clinical utility in the management of KOA. Geriatr Gerontol Int 2024; 24: 415-420.


Asunto(s)
Neoplasias , Osteoartritis de la Rodilla , Humanos , Anciano , Osteoartritis de la Rodilla/terapia , Pulgar , Interleucina-6/uso terapéutico , Inducción Percutánea del Colágeno , Dolor , Resultado del Tratamiento
2.
J Agric Food Chem ; 71(41): 15417-15428, 2023 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-37814909

RESUMEN

Yeast flocculation and viability are critical factors in beer production. Adequate flocculation of yeast at the end of fermentation helps to reduce off-flavors and cell separation, while high viability is beneficial for yeast reuse. In this study, we used comparative genomics to analyze the genome information on Saccharomyces pastorianus W01, and its spontaneous mutant W02 with appropriate weakened flocculation ability (better off-flavor reduction performance) and unwanted decreased viability, to investigate the effect of different gene expressions on yeast flocculation or/and viability. Our results indicate that knockout of CNE1, CIN5, SIN3, HP-3, YPR170W-B, and SCEPF1_0274000100 and overexpression of CNE1 and ALD2 significantly decreased the flocculation ability of W01, while knockout of EPL1 increased the flocculation ability of W01. Meanwhile, knockout of CIN5, YPR170W-B, OST5, SFT1, SCEPF1_0274000100, and EPL1 and overexpression of SWC3, ALD2, and HP-2 decreased the viability of W01. CIN5, EPL1, SCEPF1_0274000100, ALD2, and YPR170W-B have all been shown to affect yeast flocculation ability and viability.


Asunto(s)
Saccharomyces cerevisiae , Saccharomyces , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Floculación , Saccharomyces/genética , Saccharomyces/metabolismo , Genómica , Cerveza/análisis , Fermentación
3.
BMJ Support Palliat Care ; 13(e1): e129-e135, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32917649

RESUMEN

OBJECTIVES: This study aimed to compare depression, anxiety and quality of life (QoL) between cachexia and non-cachexia patients, and explore the relationship between cachexia and depression, anxiety and QoL in patients with cancer. METHODS: A total of 528 patients from cancer centres of four hospitals were enrolled in this cross-sectional study. All patients were divided into cachexia and non-cachexia according to international consensus definition of cachexia. Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7) and Quality of Life Questionnaire-Cancer 30 (QLQ-C30) were used to evaluate depression, anxiety and QoL. RESULTS: 285 patients (53.98%) were classified as cachexia. The prevalence of depression, anxiety, severe depression and severe anxiety in cachexia was 30.2%, 18.6%, 6.7% and 8.4%, respectively, which were significantly higher than in non-cachexia (all p<0.01). Patients with cachexia obviously acquired poorer physical function (PF), role function (RF), cognitive function (CF), emotional function (EF), social function (SF) and overall QoL than non-cachexia patients (all p<0.01). Cachexia was positively associated with depression (unstandardised coefficient (B)=2.123, p<0.001) and anxiety (B=1.123, p=0.024), and had a negative relationship with PF, CF, EF, SF and overall QoL (all B<0, all p<0.05). CONCLUSIONS: Cachexia was associated with greater depression and anxiety and poorer QoL in patients with cancer, which emphasised the importance of timely identification and management of cachexia to improve the psychological problems and QoL among patients with cancer.


Asunto(s)
Neoplasias , Calidad de Vida , Humanos , Calidad de Vida/psicología , Depresión/epidemiología , Depresión/psicología , Estudios Transversales , Caquexia/epidemiología , Caquexia/etiología , Ansiedad/epidemiología , Ansiedad/psicología , Trastornos de Ansiedad , Encuestas y Cuestionarios , Neoplasias/complicaciones
4.
Front Pharmacol ; 12: 731386, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34867338

RESUMEN

Background: Cachexia is a multifactorial disorder characterized by weight loss and muscle wasting, making up for about 20% of cancer-related death. However, there are no effective drugs to combat cachexia at present. Methods: In this study, the effect of CT26 exosomes on C2C12 myotubes was observed. We compared serum HMGB1 level in cachexia and non-cachexia colon cancer patients. We further explored HMGB1 expression level in CT26 exosome. We added recombinant HMGB1 to C2C12 myotubes to observe the effects of HMGB1 on C2C12 myotubes and detected the expression level of the muscle atrophy-related proteins. Then, we used the HMGB1 inhibitor glycyrrhizin to reverse the effects of HMGB1 on C2C12 myotubes. Finally, HMGB1 inhibitor glycyrrhizin was utilized to relieve cachexia in CT26 cachexia mouse model. Results: Exosomes containing HMGB1 led to muscle atrophy with significantly decreased myotube diameter and increased expression of muscle atrophy-related proteins Atrogin1 and MuRF1. Further, we detected that HMGB1 induced the muscle atrophy mainly via TLR4/NF-κB pathway. Administration of the HMGB1 inhibitor glycyrrhizin could relieve muscle wasting in vitro and attenuate the progression of cachexia in vivo. Conclusion: These findings demonstrate the cachectic role of HMGB1, whether it is soluble form of HMGB1 or secreted from tumor cells as part of exosomes. HMGB1 inhibitor glycyrrhizin might be a promising drug in colon cancer cachexia.

5.
J Clin Psychol Med Settings ; 28(2): 212-220, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-32040797

RESUMEN

The distress thermometer (DT) is a commonly used tool for screening distress in Asian patients with cancer. However, the optimal cut-off score and discriminative accuracy remain unclear. Hence, this meta-analysis aimed to examine its diagnostic value and optimal cut-off score in Asia. A systematic search was conducted in the PubMed, EMBASE and Cochrane Library databases. The pooled sensitivity, specificity, positive and negative predictive values, and diagnostic odds ratio were calculated. The area under the curve (AUC) was computed from the summary receiver-operating characteristic (SROC) curve. All analyses were performed using STATA 12.0 software. Finally, 10 studies describing 2851 patients were included. After pooling all the results from the 10 studies, the optimal DT cut-off score was 4 with a pooled sensitivity of 0.78 (95% confidence intervals (CI) 0.68-0.86), specificity of 0.73 (95% CI 0.65-0.80) and AUC of 0.82 (95% CI 0.78-0.85). When the DT was compared to the hospital anxiety and depression scale-total (HADS-T), the cut-off score of 4 showed the best balance between the pooled sensitivity (0.81, 95% CI 0.69-0.89) and specificity (0.74, 95% CI 0.59-0.84), and the AUC was 0.84 (95% CI 0.81-0.87). In conclusion, the DT with a cut-off score of 4 was an effective screening tool in Asian patients with cancer.


Asunto(s)
Neoplasias , Termómetros , Detección Precoz del Cáncer , Humanos , Tamizaje Masivo , Neoplasias/complicaciones , Neoplasias/diagnóstico , Sensibilidad y Especificidad , Estrés Psicológico
6.
Environ Sci Ecotechnol ; 6: 100092, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36159180

RESUMEN

In this study, an Escherichia coli (E. coli) whole-cell biosensor for the specific detection of bioavailable arsenic was developed by placing a green fluorescent protein (GFP) reporter gene under the control of the ArsR1 (GSU2952) regulatory circuit from Geobacter sulfurreducens. E. coli cells only emitted green fluorescence in the presence of arsenite and were more sensitive to arsenite when they were grown in M9 supplemented medium compared to LB medium. Under optimal test conditions, the Geobacter arsR1 promoter had a detection limit of 0.01 µM arsenite and the GFP expression was linear within a range of 0.03-0.1 µM (2.25-7.5 µg/l). These values were well below World Health Organization's drinking water quality standard, which is 10 µg/l. The feasibility of using this whole-cell biosensor to detect arsenic in water samples, such as arsenic polluted tap water and landfill leachate was verified. The biosensor was determined to be just as sensitive as atomic fluorescence spectrometry. This study examines the potential applications of biosensors constructed with Geobacter ArsR-P ars regulatory circuits and provides a rapid and cost-effective tool that can be used for arsenic detection in water samples.

7.
Nutrition ; 82: 111032, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33172686

RESUMEN

OBJECTIVES: Sarcopenia is a well-known risk factor for inferior cancer outcomes, but the identification of patients at risk remains challenging. A new sarcopenia index (SI), defined as serum creatinine (Cr) × cystatin C (CysC)-based glomerular filtration rate (eGFRCysC), has been reported to be an objective surrogate marker for sarcopenia. The aim of this study was to assess whether the SI is associated with sarcopenia and cancer-related fatigue (CRF) in patients with advanced cancer. METHODS: This cross-sectional study included 182 patients with different types of cancer (cancer stages III/IV; mean age 55.1 ± 11.1 y). Sarcopenia was defined as the presence of both low muscle mass and low muscle strength. The cross-sectional area of skeletal muscle mass (SMA) at the third lumbar spine was estimated by computed tomography (CT). Low muscle mass was defined as a skeletal muscle index (SMA/height2) <34.9 cm2/m2 for women and 40.8 cm2/m2 for men. Low muscle strength was determined by handgrip strength (HGS) according to the cutoffs of the Asian Working Group for Sarcopenia (<18 kg for women and <26 kg for men). CRF was measured by the Brief Fatigue Inventory (BFI). The associations between SI with both sarcopenia and CRF were investigated. RESULTS: The prevalence of sarcopenia was 27.5%. The SI was significantly lower in both the sarcopenia and severe fatigue groups. The associations between SI and SMA (r = 0.365; P < 0.001), skeletal muscle index (SMI) (r = 0.340; P < 0.001), and HGS (r = 0.414; P <0 .001) were stronger than the associations between the serum creatinine/cystatin C (Cr/CysC) ratio and SMA (r = 0.299; P < 0.001), SMI (r = 0.269; P <0 .001), and HGS (r = 0.364; P <0 .001). Additionally, a decrease in the SI was associated with a higher likelihood of sarcopenia (odds ratio per 10-unit, 1.09; 95% confidence interval, 1.02-1.16) after adjusting for potential confounding factors. However, there was only a weak correlation between the SI and BFI score (r = -0.161, P = 0.045). CONCLUSION: The SI might be a useful objective tool for assessing sarcopenia in patients with advanced cancer. Further studies are warranted to extend the present findings.


Asunto(s)
Creatinina , Cistatina C , Neoplasias , Sarcopenia , Adulto , Anciano , Creatinina/sangre , Estudios Transversales , Cistatina C/sangre , Femenino , Fuerza de la Mano , Humanos , Masculino , Persona de Mediana Edad , Músculo Esquelético/patología , Neoplasias/complicaciones , Neoplasias/patología , Sarcopenia/diagnóstico , Sarcopenia/epidemiología , Sarcopenia/etiología
8.
Clin Nutr ; 39(11): 3337-3345, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32143888

RESUMEN

BACKGROUND & AIMS: Sarcopenia is a commonly prevalent malnutrition condition and serves as a valuable adverse prognostic indicator for survival in patients with cancer. A rapid and convenient screening test for sarcopenia would be helpful for patients. Aim of the study was to evaluate the diagnostic value of SARC-F and SARC-F combined with calf circumference (SARC-CalF) for screening cancer-related sarcopenia in cancer population. METHODS: A total of 309 patients with cancer who had routine abdominal comptued tomography (CT) images within 30 days were enrolled in this cross-sectional cohort. Sarcopenia was determined as the presence of both low muscle mass (LMM) and low muscle strength; muscle mass was evaluated by CT-scan, and muscle strength was evaluated by handgrip strength (HGS). Two different diagnostic criteria (Western criteria and Eastern criteria) were used as the reference standards. The sensitivity and specificity analyses of the SARC-F and SARC-CalF were calculated. The receiver operating characteristic (ROC) curves and the area under the ROC curves (AUC) were used to compare the diagnostic value of SARC-F and SARC-CalF for sarcopenia. RESULTS: The prevalence of LMM and sarcopenia in the patient group was 85.1% and 50.5% by Western criteria. Corresponding figures were lower as 42.4% and 26.2% by Eastern criteria. In the overall study population, when sarcopenia defined by the Eastern criteria, sensitivity and specificity of SARC-CalF were 66.6% and 70.1%, whereas that of SARC-F were 32.1% and 90.7%, respectively. The AUCs for SARC-CalF and SARC-F were 0.75 (95% confidence interval (CI) 0.70-0.80) and 0.70 (95% CI 0.64-0.75), respectively (P = 0.003). Against the Western criteria, SARC-CalF also had better sensitivity (55.1% vs. 22.4%) but lower specificity (76.4% vs. 92.1%) than that of SARC-F. The AUCs of SARC-CalF and SARC-F were 0.70 (95% CI 0.65-0.75) and 0.68 (95% CI 0.62-0.73), respectively, but the difference was not significant (P = 0.211). CONCLUSIONS: SARC-CalF significantly increases the sensitivity and overall diagnostic accuracy of SARC-F for screening sarcopenia. SARC-CalF can be a rapid screening tool for sarcopenia in patients with cancer.


Asunto(s)
Antropometría/métodos , Tamizaje Masivo/métodos , Neoplasias/fisiopatología , Sarcopenia/diagnóstico , Tomografía Computarizada por Rayos X/estadística & datos numéricos , Abdomen/diagnóstico por imagen , Anciano , Estudios Transversales , Femenino , Fuerza de la Mano , Humanos , Masculino , Persona de Mediana Edad , Neoplasias/complicaciones , Valor Predictivo de las Pruebas , Pronóstico , Curva ROC , Estándares de Referencia , Sarcopenia/etiología , Sensibilidad y Especificidad , Tibia/patología , Tomografía Computarizada por Rayos X/métodos
9.
RSC Adv ; 10(12): 6953-6959, 2020 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-35493916

RESUMEN

Polybenzoxazines with molecular design flexibility have excellent properties by using suitable raw materials. A new benzoxazine monomer terephthalic acid bis-[2-(6-methyl-4H-benzo[e][1,3]oxazin-3-yl)]ethyl ester (TMBE) with bis-ester groups has been synthesized from the simple esterification reaction of terephthaloyl chloride and 2-(6-methyl-4H-benzo[e][1,3]oxazin-3-yl)-ethanol (MB-OH). The chemical structure of TMBE was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (1H-NMR, 13C-NMR). Polymerization behavior of TMBE was studied by differential scanning calorimetry (DSC) and FT-IR after each cure stage. The cross-linked polybenzoxazine (PTMBE) gave a transparent film through the thermal casting method. The dynamic mechanical analysis of PTMBE showed that the T g was 110 °C. Thermogravimetric analysis reveals better thermal stability as evidenced by the 5% and 10% weight-loss temperatures (T d5 and T d10) of PTMBE, which were 263 and 289 °C, respectively, with a char yield of 27% at 800 °C. The tensile test of the film revealed that the elongation at break was up to 14.2%.

10.
Biotechnol Biofuels ; 12: 49, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30899329

RESUMEN

BACKGROUND: The thermotolerant yeast Kluyveromyces marxianus is a potential candidate for high-temperature fermentation. When K. marxianus was used for high-temperature ethanol fermentation, a fermentation arrest was observed during the late fermentation stage and the stress responses have been investigated based on the integration of RNA-Seq and metabolite data. In order to bring new insights into the cellular responses of K. marxianus after the fermentation arrest during high-temperature ethanol fermentation, quantitative proteomic profiling and integrated analysis with transcriptomic data were performed in this study. RESULTS: Samples collected at 14, 16, 18, 20 and 22 h during high-temperature fermentation were subjected to isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic profiling and integrated analysis with transcriptomic data. The correlations between transcripts and proteins for the comparative group 16 h vs 14 h accounted for only 4.20% quantified proteins and 3.23% differentially expressed proteins (DEPs), respectively, much higher percentages of correlations (30.56%-59.11%) were found for other comparative groups (i.e., 18 h vs 14 h, 20 h vs 14 h, and 22 h vs 14 h). According to Spearman correlation tests between transcriptome and proteome (the absolute value of a correlation coefficient between 0.5 and 1 indicates a strong correlation), poor correlations were found for all quantified proteins (R = - 0.0355 to 0.0138), DEPs (R = - 0.0079 to 0.0233) and the DEPs with opposite expression trends to corresponding differentially expressed genes (DEGs) (R = - 0.0478 to 0.0636), whereas stronger correlations were observed in terms of the DEPs with the same expression trends as the correlated DEGs (R = 0.5593 to 0.7080). The results of multiple reaction monitoring (MRM) verification indicate that the iTRAQ results were reliable. After the fermentation arrest, a number of proteins involved in transcription, translation, oxidative phosphorylation and fatty acid metabolism were down-regulated, some molecular chaperones and proteasome proteins were up-regulated, the ATPase activity significantly decreased, and the total fatty acids gradually accumulated. In addition, the contents of palmitic acid, oleic acid, C16, C18, C22 and C24 fatty acids increased by 16.77%, 28.49%, 14.14%, 26.88%, 628.57% and 125.29%, respectively. CONCLUSIONS: This study confirmed some biochemical and enzymatic alterations provoked by the stress conditions in the specific case of K. marxianus: such as decreases in transcription, translation and oxidative phosphorylation, alterations in cellular fatty acid composition, and increases in the abundance of molecular chaperones and proteasome proteins. These findings provide potential targets for further metabolic engineering towards improvement of the stress tolerance in K. marxianus.

11.
Appl Microbiol Biotechnol ; 103(6): 2715-2729, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30673809

RESUMEN

The thermotolerant Kluyveromyces marxianus is a potential candidate for high-temperature ethanol fermentation. Although K. marxianus exhibited high ethanol productivity at 45 °C during the early fermentation stage, we observed a fermentation arrest due to the accumulated inhibitors. The stress responses of K. marxianus during high-temperature fermentation were revealed based on integration of RNA sequencing (RNA-Seq) and metabolite data. High temperature stimulated mitochondrial respiration but repressed the tricarboxylic acid (TCA) cycle, leading to increased generation of reactive oxygen species (ROS) and a lowered ratio of reduced nicotinamide adenine dinucleotide (NADH)/oxidized nicotinamide adenine dinucleotide (NAD+). Glycerol production was enhanced during the early fermentation stage, which might contribute to NADH reoxidation and ROS generation. Excess ROS could be neutralized by reduced nicotinamide adenine dinucleotide phosphate (NADPH) that might be reserved in the following ways: (1) decreased biosynthesis of branched-chain amino acids (BCAAs) reduced NADPH consumption; (2) enhanced acetic acid production increased NADPH regeneration. The degree of fatty acid unsaturation was also reduced to adapt to high temperature. In addition, stress responses were also observed after the fermentation arrest at 45 °C. Genes related to peroxidase activity, iron-sulfur cluster assembly, and flavin mononucleotide (FMN) binding were downregulated, while genes associated with DNA repair and lipid composition of the plasma were upregulated. The yeast also produced more ergosterol to deal with ethanol stress. This study gains comprehensive insights into the K. marxianus transcriptome under various stresses during high-temperature ethanol fermentation, providing rich information for further metabolic engineering towards improved stress tolerance and ethanol production.


Asunto(s)
Etanol/metabolismo , Fermentación , Calor , Kluyveromyces/metabolismo , Estrés Fisiológico , Ácido Acético/metabolismo , Aminoácidos de Cadena Ramificada/biosíntesis , Secuencia de Bases , Ciclo del Ácido Cítrico , Glucosa/metabolismo , Kluyveromyces/genética , Ingeniería Metabólica , Mitocondrias/metabolismo , NADP/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Análisis de Secuencia de ARN , Transcriptoma
12.
Microb Biotechnol ; 12(6): 1154-1163, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-30394685

RESUMEN

CRISPR/Cas-based (clustered regularly interspaced short palindromic repeats/CRISPR-associated) screening has been proved to be an efficient method to study functional genomics from yeast to human. In this study, we report the development of a focused CRISPR/Cas-based gene activation library in Saccharomyces cerevisiae and its application in gene identification based on functional screening towards improved thermotolerance. The gene activation library was subjected to screening at 42°C, and the same library cultured at 30°C was set as a control group. After five successive subcultures, five clones were randomly picked from the libraries cultured at 30 and 42°C, respectively. The five clones selected at 30°C contain the specificity sequences of five different single guide RNAs, whereas all the five clones selected at 42°C contain the specificity sequence of one sgRNA that targets the promoter region of OLE1. A crucial role of OLE1 in thermotolerance was identified: the overexpression of OLE1 increased fatty acid unsaturation, and thereby helped counter lipid peroxidation caused by heat stress, rendering the yeast thermotolerant. This study described the application of CRISPR/Cas-based gene activation screening with an example of thermotolerant yeast screening, demonstrating that this method can be used to identify functional genes in yeast.


Asunto(s)
Edición Génica/métodos , Genética Microbiana/métodos , Respuesta al Choque Térmico , Saccharomyces cerevisiae/efectos de la radiación , Estearoil-CoA Desaturasa/metabolismo , Termotolerancia , Activación Transcripcional , Proteína 9 Asociada a CRISPR , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas , Ácidos Grasos Insaturados/metabolismo , Pruebas Genéticas/métodos , Calor , Peroxidación de Lípido , Saccharomyces cerevisiae/genética , Estearoil-CoA Desaturasa/genética
13.
Biotechnol Biofuels ; 11: 207, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30061929

RESUMEN

BACKGROUND: Low ethanol tolerance of Kluyveromyces marxianus limits its application in high-temperature ethanol fermentation. As a complex phenotype, ethanol tolerance involves synergistic actions of many genes that are widely distributed throughout the genome, thereby being difficult to engineer. TATA-binding protein is the most common target of global transcription machinery engineering for improvement of complex phenotypes. RESULTS: A random mutagenesis library of K. marxianus TATA-binding protein Spt15 was constructed and subjected to screening under ethanol stress. Two mutant strains with improved ethanol tolerance were identified, one of which (denoted as M2) exhibited increased ethanol productivity. The mutant of Spt15 in strain M2 (denoted as Spt15-M2) has a single amino acid substitution at position 31 (Lys → Glu). RNA-Seq-based transcriptomic analysis revealed cellular transcription profile changes resulting from Spt15-M2. Spt15-M2 caused changes in transcriptional level of most of the genes in the central carbon metabolism network. Compared with control strain, 444 differentially expressed genes (DEGs) were identified in strain M2 (fold change > 2, Padj < 0.05), including 48 up-regulated and 396 down-regulated. The up-regulated DEGs are involved in amino acid transport, long-chain fatty acid biosynthesis and MAPK signaling pathway, while the down-regulated DEGs are related to ribosome biogenesis, translation and protein synthesis. Five candidate genes (GAP1, GNP1, FAR1, STE2 and TEC1), which were found to be up-regulated in M2 strain, were overexpressed for a gain-of-function assay. However, the overexpression of no single gene helped improve ethanol tolerance as SPT15-M2 did. CONCLUSIONS: This work demonstrates that ethanol tolerance of K. marxianus can be improved by engineering its TATA-binding protein. A single amino acid substitution (K31E) of TATA-binding protein Spt15 is able to bring differential expression of hundreds of genes that acted as an interconnected network for the phenotype of ethanol tolerance. Future perspectives of this technique in K. marxianus were discussed.

14.
Biotechnol Biofuels ; 10: 289, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29213328

RESUMEN

BACKGROUND: High temperature inhibits cell growth and ethanol fermentation of Saccharomyces cerevisiae. As a complex phenotype, thermotolerance usually involves synergistic actions of many genes, thereby being difficult to engineer. The overexpression of either endogenous or exogenous stress-related transcription factor genes in yeasts was found to be able to improve relevant stress tolerance of the hosts. RESULTS: To increase ethanol yield of high-temperature fermentation, we constructed a series of strains of S. cerevisiae by expressing 8 transcription factor genes from S. cerevisiae and 7 transcription factor genes from thermotolerant K. marxianus in S. cerevisiae. The results of growth curve measurements and spotting test show that KmHsf1 and KmMsn2 can enhance cell growth of S. cerevisiae at 40-42 °C. According to the results of batch fermentation at 43 °C with an initial glucose concentration of 104.8 g/l, the fermentation broths of KmHSF1 and KmMSN2-expressing strains could reach final ethanol concentrations of 27.2 ± 1.4 and 27.6 ± 1.2 g/l, respectively, while the control strain just produced 18.9 ± 0.3 g/l ethanol. Transcriptomic analysis found that the expression of KmHSF1 and KmMSN2 resulted in 55 (including 31 up-regulated and 24 down-regulated) and 50 (including 32 up-regulated and 18 down-regulated) genes with different expression levels, respectively (padj < 0.05). The results of transcriptomic analysis also reveal that KmHsf1 might increase ethanol production by regulating genes related to transporter activity to limit excessive ATP consumption and promote the uptake of glucose; while KmMsn2 might promote ethanol fermentation by regulating genes associated with glucose metabolic process and glycolysis/gluconeogenesis. In addition, KmMsn2 might also help to cope with high temperature by regulating genes associated with lipid metabolism to change the membrane fluidity. CONCLUSIONS: The transcription factors KmHsf1 and KmMsn2 of thermotolerant K. marxianus can promote both cell growth and ethanol fermentation of S. cerevisiae at high temperatures. Different mechanisms of KmHsf1 and KmMsn2 in promoting high-temperature ethanol fermentation of S. cerevisiae were revealed by transcriptomic analysis.

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