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1.
Sci Rep ; 14(1): 5037, 2024 02 29.
Article in English | MEDLINE | ID: mdl-38424450

ABSTRACT

The filamentous Thermoascus aurantiacus fungus characterized by its thermophilic nature, is recognized as an exceptional producer of various enzymes with biotechnological applications. This study aimed to explore biotechnological applications using polygalacturonase (PG) derived from the Thermoascus aurantiacus PI3S3 strain. PG production was achieved through submerged fermentation and subsequent purification via ion-exchange chromatography and gel filtration methods. The crude extract exhibited a diverse spectrum of enzymatic activities including amylase, cellulase, invertase, pectinase, and xylanase. Notably, it demonstrated the ability to hydrolyze sugarcane bagasse biomass, corn residue, and animal feed. The purified PG had a molecular mass of 36 kDa, with optimal activity observed at pH 4.5 and 70 °C. The activation energy (Ea) was calculated as 0.513 kJ mol-1, highlighting activation in the presence of Ca2+. Additionally, it displayed apparent Km, Vmax, and Kcat values of at 0.19 mg mL-1, 273.10 U mL-1, and 168.52 s-1, respectively, for hydrolyzing polygalacturonic acid. This multifunctional PG exhibited activities such as denim biopolishing, apple juice clarification, and demonstrated both endo- and exo-polygalacturonase activities. Furthermore, it displayed versatility by hydrolyzing polygalacturonic acid, carboxymethylcellulose, and xylan. The T. aurantiacus PI3S3 multifunctional polygalacturonase showed heightened activity under acidic pH, elevated temperatures, and in the presence of calcium. Its multifunctional nature distinguished it from other PGs, significantly expanding its potential for diverse biotechnological applications.


Subject(s)
Saccharum , Thermoascus , Polygalacturonase/metabolism , Thermoascus/metabolism , Cellulose , Multifunctional Enzymes , Saccharum/metabolism , Hydrogen-Ion Concentration , Enzyme Stability , Temperature
2.
Braz J Microbiol ; 54(4): 2705-2718, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37735300

ABSTRACT

Endophytic fungi constitute a major part of the still unexplored fungal diversity and have gained interest as new biological sources of natural active compounds, including enzymes. Endophytic fungi were isolated from soybean leaves and initially screened on agar plates for the production of CMCase (carboxymethylcellulase), xylanase, amylase and protease. The highest Enzymatic Indexes (IE) were verified for xylanase (2.14 and 1.31) with the fungi M6-A6P5F2 and M12-A5P3F1.2 and CMCase (1.92 and 1.62) with the fungi M13-A9P2F1 and M12-A5P3F1.2, respectively. The production of xylanase and CMCase by the selected fungi was evaluated in submerged cultivation using beechwood xylan and carboxymethylcellulose (CMC), as well as sugarcane straw and bagasse in different ratios as carbon sources. Both types of lignocellulosic biomass proved to be good inducers of enzymatic activity. The best xylanase producer among the isolates was identified as Colletotrichum boninense. With this fungus, the highest xylanase activity was obtained with a sugarcane straw-bagasse mixture in a 50:50 ratio (383.63 U mL-1), a result superior to that obtained with the use of beechwood xylan (296.65 U mL-1). Regardingthe kinetic behavior of the crude xylanase, there was found optimal pH of 5.0 and optimal temperatures of 50°C and 60°C. At 40°C and 50°C, xylanase retained 87% and 76% of its initial catalytic activity, respectively. These results bring new perspectives on bioprospecting endophytic fungi for the production of enzymes, mainly xylanase, as well as the exploitation of agro-industrial by-products, such as sugarcane straw and bagasse.


Subject(s)
Saccharum , Xylans , Saccharum/microbiology , Biomass , Fungi
3.
Sci Rep ; 13(1): 12726, 2023 Aug 05.
Article in English | MEDLINE | ID: mdl-37543689

ABSTRACT

Developing accurate models for groundwater control is paramount for planning and managing life-sustaining resources (water) from aquifer reservoirs. Significant progress has been made toward designing and employing deep-forecasting models to tackle the challenge of multivariate time-series forecasting. However, most models were initially taught only to optimize natural language processing and computer vision tasks. We propose the Wavelet Gated Multiformer, which combines the strength of a vanilla Transformer with the Wavelet Crossformer that employs inner wavelet cross-correlation blocks. The self-attention mechanism (Transformer) computes the relationship between inner time-series points, while the cross-correlation finds trending periodicity patterns. The multi-headed encoder is channeled through a mixing gate (linear combination) of sub-encoders (Transformer and Wavelet Crossformer) that output trending signatures to the decoder. This process improved the model's predictive capabilities, reducing Mean Absolute Error by 31.26 % compared to the second-best performing transformer-like models evaluated. We have also used the Multifractal Detrended Cross-Correlation Heatmaps (MF-DCCHM) to extract cyclical trends from pairs of stations across multifractal regimes by denoising the pair of signals with Daubechies wavelets. Our dataset was obtained from a network of eight wells for groundwater monitoring in Brazilian aquifers, six rainfall stations, eleven river flow stations, and three weather stations with atmospheric pressure, temperature, and humidity sensors.

4.
Braz J Microbiol ; 54(3): 1559-1564, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37440124

ABSTRACT

Denim, also known as jeans, is a fabric made up of braided cotton threads dyed indigo blue, whose fibers contain approximately 10% of non-cellulosic impurities that reduce its commercial value. Microbial enzymes can act in the cleaning and desizing processes of jeans, improving their color, softness, and covering capacity. The recombinant Xylanase II (XynA2) from the aquatic bacterial Caulobacter crescentus (C. crescentus), previously characterized in terms of its biochemical features, was applied to the biotreatment of jeans to clean and degum it. The biotreatment performance was evaluated in terms of tissue weight loss, amount of reducing sugars released and analysis of the images obtained by scanning electron microscopy (SEM). Biotreated tissues, at 12 and 24 h, showed a dry weight loss of 4.9 and 6.6%, respectively. The reducing sugars amount released after XynA2 action over the jean's fibers showed statistically significant values when compared with each other and with their respective controls. SEM images clearly shown that the fabric treated for 12 h presented a smooth and polished surface, while the fabric treated for 24 h showed the cotton fibers broken, displaying severe damage to the textile. The best treatment for the jeans was in the presence of 1 U mg-1 XynA2 at pH 8 and 60 °C during 12 h. In conclusion, XynA2 of C. crescentus was satisfactorily applied for the biopolishing of denim jeans being a more sustainable alternative to the use of chemical and abrasive processes to obtain the same effects.


Subject(s)
Caulobacter crescentus , Caulobacter crescentus/genetics , Textiles , Cotton Fiber , Indigo Carmine , Coloring Agents
6.
La Plata; Gobierno de la Provincia de Buenos Aires. Subsecretaría de Salud Mental, Consumos Problemáticos y Violencias en el Ámbito de la Salud Pública; ene. 2023. 1-5 p.
Non-conventional in Spanish | LILACS | ID: biblio-1416059
7.
Sci Rep ; 12(1): 21655, 2022 12 15.
Article in English | MEDLINE | ID: mdl-36522406

ABSTRACT

Complex systems in biology, climatology, medicine, and economy hold emergent properties such as non-linearity, adaptation, and self-organization. These emergent attributes can derive from large-scale relationships, connections, and interactive behavior despite not being apparent from their isolated components. It is possible to better comprehend complex systems by analyzing cross-correlations between time series. However, the accumulation of non-linear processes induces multiscale structures, therefore, a spectrum of power-law exponents (the fractal dimension) and distinct cyclical patterns. We propose the Multifractal detrended cross-correlation heatmaps (MF-DCCHM) based on the DCCA cross-correlation coefficients with sliding boxes, a systematic approach capable of mapping the relationships between fluctuations of signals on different scales and regimes. The MF-DCCHM uses the integrated series of magnitudes, sliding boxes with sizes of up to 5% of the entire series, and an average of DCCA coefficients on top of the heatmaps for the local analysis. The heatmaps have shown the same cyclical frequencies from the spectral analysis across different multifractal regimes. Our dataset is composed of sales and inventory from the Brazilian automotive sector and macroeconomic descriptors, namely the Gross Domestic Product (GDP) per capita, Nominal Exchange Rate (NER), and the Nominal Interest Rate (NIR) from the Central Bank of Brazil. Our results indicate cross-correlated patterns that can be directly compared with the power-law spectra for multiple regimes. We have also identified cyclical patterns of high intensities that coincide with the Brazilian presidential elections. The MF-DCCHM uncovers non-explicit cyclic patterns, quantifies the relations of two non-stationary signals (noise effect removed), and has outstanding potential for mapping cross-regime patterns in multiple domains.


Subject(s)
Fractals , Meteorology , Time Factors , Research Design , Brazil
8.
Braz J Microbiol ; 53(3): 1167-1174, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35482283

ABSTRACT

Purified endoxylanase from Thermomyces lanuginosus PC7S1T was immobilized in calcium alginate, resulting in a yield of 78.5% and a reusability for 11 cycles. The stability of the immobilized enzyme was given for a pH range of 4 to 9 for 96 h. Endoxylanase immobilized in calcium alginate at 65 °C exhibited thermal stability equal to the soluble enzyme for 5 h, and at high temperatures of 75 °C and 85 °C showed half-lives of 4 and 3 h, respectively. Both soluble endoxylanase and immobilized forms were able to hydrolyze hemicellulose, obtained from low-lignin sorghum biomass pretreated with 5% H2O2 and 2% NaOH, after 1 h of incubation at 65 °C, releasing a mixture of short-chain xylooligosaccharides (X2-X6). The highest amounts of XOS generated were those for X5 (24 to 40%), X4 (33 to 39%), and X3 (11 to 22%). These XOS acted as prebiotics, promoting the growth of the probiotic L. acidophilus, similar to glucose in the MRS broth. These results show the potential of low-lignin sorghum to generate XOS with prebiotic activity, suggesting the application of these compounds in the food industry.


Subject(s)
Endo-1,4-beta Xylanases , Sorghum , Alginates , Biomass , Edible Grain , Eurotiales , Glucuronates , Hydrogen Peroxide , Hydrolysis , Lignin/chemistry , Oligosaccharides/chemistry
9.
Braz J Microbiol ; 53(3): 1133-1157, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35397075

ABSTRACT

The scientific community has been alarmed by the possible immunological evasion, higher infectivity, and severity of disease caused by the newest variants of SARS-CoV-2. The spike protein has an important role in the cellular invasion of viruses and is the target of several vaccines and therapeutic resources, such as monoclonal antibodies. In addition, some of the most relevant mutations in the different variants are on the spike (S) protein gene sequence that leads to structural alterations in the predicted protein, thus causing concern about the protection mediated by vaccines against these new strains. The present review highlights the most recent knowledge about COVID-19 and vaccines, emphasizing the different spike protein structures of SARS-CoV-2 and updating the reader about the emerging viral variants and their classifications, the more common viral mutations described and their distribution in Brazil. It also compiles a table with the most recent knowledge about all of the Omicron spike mutations.


Subject(s)
SARS-CoV-2 , Spike Glycoprotein, Coronavirus/genetics , Antibodies, Neutralizing , Antibodies, Viral , COVID-19 , Humans , Mutation , SARS-CoV-2/genetics , Viral Envelope Proteins/genetics
10.
J Appl Microbiol ; 132(4): 2832-2843, 2022 Apr.
Article in English | MEDLINE | ID: mdl-34850500

ABSTRACT

AIMS: The objective of this study was to determine the best conditions to produce invertase by Cunninghamella echinulata PA3S12MM and to immobilize and apply the enzyme. METHODS AND RESULTS: The maximum production was verified in 8 days of cultivation at 28°C supplemented with 10 g L-1 apple peel, reaching 1054.85 U ml-1 . The invertase was purified from the DEAE-Sephadex column. The derivative immobilized in alginate-gelatin-calcium phosphate showed reusability >50% for 19 cycles. The derivative immobilized in glutaraldehyde-chitosan showed greater thermostability and at a different pH. The hydrolysis of 15 ml of sucrose 500 g L-1 in a fixed bed reactor (total volume of 31 ml) produced 24.44 µmol min-1 of glucose and fructose at a residence time of 30 min and a conversion factor of 0.5. CONCLUSIONS: The new wild strain C. echinulata PA3S12MM presents high invertase production in medium supplemented with an agro-industrial residue and the immobilized enzyme showed high thermal stability and resistance at a different pH. SIGNIFICANCE AND IMPACT OF THE STUDY: The fungus C. echinulata PA3S12MM is an excellent producer of invertases in Vogel medium supplemented with apple peel. The enzyme is promising for industrial application since it has good performance in reusability and inverted sugar production.


Subject(s)
Cunninghamella , beta-Fructofuranosidase , Cunninghamella/metabolism , Enzyme Stability , Enzymes, Immobilized , Fructose , Hydrogen-Ion Concentration , Temperature , beta-Fructofuranosidase/metabolism
11.
Diagnostics (Basel) ; 11(11)2021 Oct 30.
Article in English | MEDLINE | ID: mdl-34829367

ABSTRACT

Despite tremendous progress being made in recent years, multiple myeloma (MM) remains a challenging disease. The laboratory plays a critical role in the overall management of patients. The diagnosis, prognosis, clinical monitoring and evaluation of the response are key moments in the clinical care process. Conventional laboratory methods have been and continue to be the basis of laboratory testing in monoclonal gammopathies, along with the serum free light chain test. However, more accurate methods are needed to achieve new and more stringent clinical goals. The heavy/light chain assay is a relatively new test which can overcome some of the limitations of the conventional methods for the evaluation of intact immunoglobulin MM patients. Here, we report an update of the evidence accumulated in recent years on this method regarding its use in MM.

12.
Ann Anat ; 238: 151793, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34186201

ABSTRACT

INTRODUCTION: The etiologies of most chronic temporomandibular joint disorders are unknown. However, an association between habitual chewing on a particular side and chronic temporomandibular joint disorders has been reported. The aim of this study was to investigate the differences between sides (affected vs unaffected) of biodynamic factors (including lateral dental guidance determined by dental anatomy) or condylar path angles (determined by temporomandibular joint morphology) and chewing function (physiological alternate chewing vs single habitual chewing side). The study scope was to investigate possible etiological factors to improve the understanding of temporomandibular joint disorders. The null hypothesis was that no difference would be found between sides that are or are not affected by chronic temporomandibular joint disorders in chewing function or in levels of dental or temporomandibular joint remodeling. METHODS: This cross-sectional, double-blind study involved 24 adults with substantial, chronic, unilateral symptoms diagnosed as temporomandibular joint disorders. Chewing function, temporomandibular joint remodeling (using axiography) and dental anatomy (lateral guidance angles using kinesiography) were assessed. RESULTS: Habitual chewing on one particular side was observed in 17 of 24 participants; significantly more (n=15) chewed on the affected side than on the unaffected side (P=0.002 in a two-tailed Fisher's exact test; risk estimate=4.5; 95% CI 1.326-15.277). The condylar path (CP) angle was steeper on the affected side than on the unaffected side (mean (standard deviation)=50.52° (9.98°) versus 45.50° (7.98°); P=0.002 in a two-tailed t-test). The lateral guidance (LG) angles were flatter on the affected side in all 24 participants. CONCLUSION: Our results suggest that habitual chewing on one side may be associated with increasing condylar path, with flattening lateral guidance angles, and also with chronic temporomandibular joint disorder on the habitual chewing side.


Subject(s)
Mastication , Temporomandibular Joint Disorders , Adult , Cross-Sectional Studies , Double-Blind Method , Humans , Mandibular Condyle , Temporomandibular Joint
13.
Front Oncol ; 11: 599532, 2021.
Article in English | MEDLINE | ID: mdl-33767978

ABSTRACT

Despite the outstanding progresses in Multiple Myeloma treatment options in the last decades, it remains an incurable disease nowadays. Infectious events are a complication due to an impaired immune system associated with MM, sometimes a life-threatening one, particularly on the first months after the diagnosis. Both the underlying disease and treatment can contribute to the infection risk, so a biomarker that assess this risk could be highly relevant for a more tailored management of the patient. The measurement of the heavy+light chain (HLC) pairs of immunoglobulins in serum allows the quantification of both the monoclonal component and the non-monoclonal immunoglobulin of the same isotype. This approach has demonstrated high sensitivity for the detection of the clonality and prognostic value for MM. HLC pair suppression itself has prognostic power and it has been proposed to be a reflection of the immune system' attempt to control the tumor. In this study we evaluated the impact of the HLC pair suppression on the rate of bloodstream infections (BSI) and early death in 115 newly diagnosed MM patients. Twenty-one percent of the patients suffered a BSI in the first 6 months after diagnosis, of which 58% died within this period, accounting to 67% of the early deaths in global and highlighting the major impact of infections on MM patients in a "real world" setting. Severe HLC pair suppression identified patients with a higher risk of early BSI (HR: 6,97, p=0,009), and extreme HLC pair suppression together with BSI event and age >65 were independent risk factors for early death (p<0,001). Based on these factors, a stratification model was generated to allow identify patients at a higher risk of early death and poorer OS, with an apparently better performance than the ISS on the early death context. In conclusion, HLC pair suppression associates with both a higher risk of life-threatening early infection and early death in newly diagnosed MM patients. Patients older than 65 with extreme HLC pair suppression and BSI are at a high risk of early death, and thus patients presenting with these criteria have a very adverse prognosis.

14.
J Food Biochem ; 45(4): e13654, 2021 04.
Article in English | MEDLINE | ID: mdl-33595123

ABSTRACT

The Cunninghamella echinulata PA3S12MM fungus is a great producer of invertases in a growth medium supplemented by apple peels. The enzyme was purified 4.5 times after two chromatographic processes, and it presented a relative molecular mass of 89.2 kDa. The invertase reached maximum activity at pH of 6 and at 60°C, in addition to presenting stability in alkaline pH and thermal activation at 50°C. The enzymatic activity increased in the presence of Mn2+ and dithiothreitol (DTT), while Cu2+ and Z2+ ions inhibited it. Also, DTT showed to protect enzymatic activity. The apparent values for Km , Vmáx , and Kcat for the sucrose hydrolysis were, respectively, 173.8 mmol/L, 908.7 mmol/L min-1 , and 1,388.79 s-1 . The carbohydrate content was of 83.13%. The invertase presented hydrolytic activity over different types of glycosidic bonds, such as α1 â†” 2ß (sucrose), α1 â†’ 4 (polygalacturonic acid), α1 â†’ 4 and α1 â†’ 2 (pectin), and α1 â†” 1 (trehalose), indicating that the enzyme is multifunctional. Thus, the biochemical properties showed by the C. echinulata PA3S12MM suggest a broad industrial application, such as in the biomass hydrolysis or in the food industry. PRACTICAL APPLICATIONS: Invertases are hydrolytic enzymes employed in several industrial sectors. Given their great importance for the economy and several industrial sectors, there is a growing interest in microorganisms producing this enzyme. The analysis of the biochemical properties of invertase in C. echinulata PA3S12MM suggest applications in the food industry. Due to its increased hydrolytic activity, the hydrolysis process of the sucrose may employ invertase for the production of invert sugar. The stability at alkaline pH suggests an application in the development of enzymatic electrodes for the quantification of sucrose in food and beverage. The multifunctional activity may work in the biomass hydrolysis or saccharification of by-products for the extraction of fermentable sugars. The high level of invertase N-linked glycosylation of invertase grants this enzyme thermal stability at high temperatures, in addition to resistance against the action of proteases, which are desirable characteristics for the application of this enzyme in industrial processes.


Subject(s)
Cunninghamella , beta-Fructofuranosidase , Hydrogen-Ion Concentration , Temperature
16.
Rev. cuba. med. gen. integr ; 36(3): e1207, jul.-set. 2020. tab
Article in Spanish | LILACS, CUMED | ID: biblio-1138977

ABSTRACT

Introducción: El embarazo en la adolescencia se ha convertido en un fenómeno de alcance mundial, lo que ha traído aparejado el aumento de las complicaciones propias de una gestación en este período de la vida; de ahí la importancia del estudio constante del comportamiento de este suceso. Objetivo: Identificar el comportamiento de importantes variables relativas a las embarazadas adolescentes. Métodos: Se efectuó una investigación descriptiva transversal en el Policlínico Docente 30 de Noviembre de Santiago de Cuba, durante los años 2016 y 2017, a partir de las historias obstétricas de las adolescentes que se embarazaron y parieron en esos años. Se seleccionaron variables de interés como edad, edad gestacional a la captación, edad de inicio de las relaciones sexuales, escolaridad, deserción escolar, evaluación nutricional a la captación, además de la edad de la pareja sexual y el peso del niño al nacer. Resultados: Las adolescentes mostraron una media de inicio de las relaciones sexuales de 15,7 años de edad, el mayor por ciento de deserciones escolares fue en la secundaria básica, las edades de las parejas sexuales entre 20 y 39 años tuvo mayor frecuencia y las que fueron evaluadas con peso deficiente a la captación aportaron mayor cantidad de recién nacidos con bajo peso. Conclusiones: El estudio frecuente del comportamiento del embarazo en la etapa de adolescencia es determinante en el enfrentamiento a este fenómeno y constituye un arma esencial para el mejoramiento del estado de salud de la población en este grupo de edad(AU)


Introduction: Adolescent pregnancy has become a worldwide phenomenon, which has brought about the increase in complications typical of childbearing in this period of life; hence, the importance of constant study about the behavior of this event. Objective: To identify the behavior of important variables concerning pregnant adolescents. Methods: A cross-sectional and descriptive research was carried out at 30 de Noviembre Teaching Polyclinic in Santiago de Cuba, during the years 2016 and 2017, based on the obstetric histories of the adolescents who became pregnant and gave birth in those years. Variables of interest were selected, such as age, gestational age at first prenatal visit, age of onset of sexual intercourse, schooling, dropout, nutritional assessment at first prenatal visit, in addition to the age of the sexual partner and the child weight at birth. Results: The adolescents showed a mean of onset of sexual relations of 15.7 years, the highest percentage of school dropouts corresponded to the basic secondary school, the ages of their sexual partners between 20 and 39 years were more frequent, and those were evaluated with deficient weight at first prenatal visit contributed a greater number of newborns with low weight. Conclusions: The frequent study of pregnancy background in the adolescent stage is decisive in coping with this phenomenon and constitutes an essential resource for improving the health status of the population in this age group(AU)


Subject(s)
Humans , Female , Pregnancy , Adolescent , Pregnancy in Adolescence/prevention & control , Coitus , Epidemiology, Descriptive , Cross-Sectional Studies
17.
Rev Esp Enferm Dig ; 112(9): 740-741, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32755142

ABSTRACT

We present the unique case of a young female woman with an infected left liver hematoma as a complication of a previous endoscopic retrograde cholangiopancreatography for a choledocolithiasis. Urgent liver resections are rarely indicated and are usually performed in cases of important liver trauma. To our knowledge this is the first case of an urgent liver resection for the rare indication of late hepatic infected hematoma after an ERCP.


Subject(s)
Cholangiopancreatography, Endoscopic Retrograde , Liver Diseases , Female , Gastrointestinal Hemorrhage , Hematoma/diagnostic imaging , Hematoma/etiology , Hematoma/surgery , Humans , Liver Diseases/diagnostic imaging , Liver Diseases/etiology , Liver Diseases/surgery
18.
Mol Biol Rep ; 47(6): 4427-4438, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32424521

ABSTRACT

Biotechnology offers innovative alternatives for industrial bioprocesses mainly because it uses enzymes that biodegrade the hemicellulose releasing fermentable sugars. Caulobacter crescentus (C. crescentus) has seven genes responsible for xylanolytic cleavage, 5 to ß-xylosidases (EC 3.2.1.37) and 2 for endoxylanases, like xynA2 (CCNA_03137) that encodes Xylanase II (EC 3.2.1.8) of the glycohydrolases-GH10 group. The xynA2 gene was amplified by PCR, cloned into the pTrcHisA vector e efficiently overexpressed in E. coli providing a His-tag fusion protein. Recombinant xylanase (XynA2) was purified by affinity chromatography using a nickel sepharose column and exhibited a single 43 kDa band on SDS-PAGE gel. XynA2 showed an optimum alkaline pH (8) and stability at alkaline pH for 24 h. Although C. crescentus is mesophilic, XynA2 has optimum temperature of 60 °C and is thermo-resistance at 65 °C. XynA maintains 66% of the enzymatic activity at high temperatures (90 °C) without being denatured.The enzyme displayed a xylanolitic activity free of cellulase to xylan from beechwood and it was not inhibited in the presence of 50 µmol mL-1 of xylose. In addition, dithiothreitol (DTT) induced XynA2 activity, as it improved its kinetic parameters by lowering the KM (5.78 µmol mL-1) and increasing the KCat/KM ratio (1.63 U s-1). Finally, C. crescentus XynA2 efficiently hydrolyzed corn straw with high release of reducing sugars that can be applied in different branches of the industry.


Subject(s)
Caulobacter crescentus/genetics , Endo-1,4-beta Xylanases/biosynthesis , Endo-1,4-beta Xylanases/isolation & purification , Biomass , Chromatography, Affinity/methods , Cloning, Molecular/methods , Endo-1,4-beta Xylanases/metabolism , Enzyme Stability , Hydrogen-Ion Concentration , Hydrolysis , Kinetics , Recombinant Proteins/genetics , Substrate Specificity , Temperature , Xylans/metabolism , Xylosidases
19.
Mol Biol Rep ; 47(2): 1499-1505, 2020 Feb.
Article in English | MEDLINE | ID: mdl-31786767

ABSTRACT

The role of the clpB gene encoding HSP/chaperone ClpB was evaluated in the multiresistant antibiotic cells of Acinetobacter baumannii (RS4 strain) under stress-induced heat shock and different beta-lactams. The expression of the clpB gene was assessed by qPCR during heat shock at 45 °C and subinhibitory concentrations of ampicillin (30 µg mL-1), amoxicillin + sulbactam (8/12 µg mL-1), cefepime (30 µg mL-1), sulfamethoxazole + trimethoprim (120/8 µg mL-1) and meropenem (18 µg mL-1). The results indicated a transient increase in clpB transcription in all treatments except cefepime. Both in the presence of ampicillin and amoxicillin/sulbactam for 20 min, the mRNA-clpB synthesis was 1.4 times higher than that of the control at time zero. Surprisingly, the mRNA-clpB levels were more than 30-fold higher after 10 min of incubation with meropenem and more than eightfold higher in the presence of trimethoprim/sulfamethoxazole. In addition, western blot assays showed that the RS4 strain treated with meropenem showed a marked increase in ClpB protein expression. Our data indicate that during exposure to beta-lactams, A. baumannii adjusts the transcription levels of the clpB mRNA and protein to respond to stress, suggesting that the chaperone may act as a key cellular component in the presence of antibiotics in this bacterium.


Subject(s)
Acinetobacter baumannii/genetics , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Gene Expression Regulation, Bacterial/drug effects , Genes, Bacterial , Heat-Shock Response/genetics , Up-Regulation/genetics , beta-Lactams/pharmacology , Acinetobacter baumannii/drug effects , Bacterial Proteins/metabolism , Heat-Shock Response/drug effects , Up-Regulation/drug effects
20.
Braz. arch. biol. technol ; 63: e20190185, 2020. tab, graf
Article in English | LILACS | ID: biblio-1132193

ABSTRACT

Abstract The second-generation bioethanol employs lignocellulosic materials degraded by microbial cellulases in their production. The fungus Trichoderma reesei is one of the main microorganisms producing cellulases, and its genetic modification can lead to the optimization in obtaining hydrolytic enzymes. This work carried out the deletion of the sequence that encodes the zinc finger motif of the transcription factor ACE1 (cellulase expression repressor I) of the fungus T. reesei RUT-C30. The transformation of the RUT-C30 lineage was confirmed by amplification of the 989 bp fragment relative to the selection marker, and by the absence of the zinc finger region amplification in mutants, named T. reesei RUT-C30Δzface1. The production of cellulases by mutants was compared to RUT-C30 and measured with substrates carboxymethylcellulose (CMC), microcrystalline cellulose (Avicel®) and Whatman filter paper (PF). The results demonstrated that RUT-C30Δzface1 has cellulolytic activity increased 3.2-fold in Avicel and 2.1-fold in CMC and PF. The mutants presented 1.4-fold higher sugar released in the hydrolysis of the biomass assays. These results suggest that the partial deletion of ace1 gene is an important strategy in achieving bioethanol production on an industrial scale at a competitive price in the fuel market.


Subject(s)
Trichoderma/enzymology , Cellulase/biosynthesis , Zinc Fingers , Biomass , Ethanol , Biofuels
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