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1.
Anticancer Res ; 39(10): 5393-5401, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31570434

RESUMO

BACKGROUND/AIM: Local recurrence of hepatocellular carcinoma (HCC) after thermal coagulation therapy may be associated with an aggressive phenotypic change. This study focused on the thermal effects on HCC cells and evaluated the heat shock response and phenotypic changes after heat treatment. MATERIALS AND METHODS: HepG2 and HuH7 cells were used. After heat treatment at 37-50°C for 5-30 min, we assessed their survival rate, induction of heat shock protein (HSP)70 promoter, proliferation rate, induction of the epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC)-related markers. RESULTS: Induction of HSP70 promoter per surviving cell was maximized after 10 min of heat treatment at 48°C. Induction of EMT and CSC-related markers was also observed. CONCLUSION: Sub-lethal heat treatment causes large heat shock response to surviving HCC cells and induce EMT-like and CSC-like phenotypic changes that might contribute to increased aggressiveness.


Assuntos
Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Resposta ao Choque Térmico/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Linhagem Celular Tumoral , Sobrevivência Celular/genética , Transição Epitelial-Mesenquimal/genética , Proteínas de Choque Térmico HSP70/genética , Células Hep G2 , Temperatura Alta , Humanos , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/patologia , Células-Tronco Neoplásicas/patologia , Taxa de Sobrevida
2.
Zhonghua Liu Xing Bing Xue Za Zhi ; 40(8): 960-964, 2019 Aug 10.
Artigo em Chinês | MEDLINE | ID: mdl-31484261

RESUMO

Objective: To study the lag effect of temperature and the source of heterogeneity on other infectious diarrhea (OID) in Zhejiang province, so as to identify related vulnerable populations at risk. Methods: Data on OID and meteorology in Zhejiang province from 2014 to 2016 were collected. A two-stage model was conducted, including: 1) using the distributed lag non-linear model to estimate the city-specific lag effect of temperature on OID, 2) applying the multivariate Meta- analysis to pool the estimated city-specific effect, 3) using the multivariate Meta-regression to explore the sources of heterogeneity. Results: There were 301 593 cases of OID in Zhejiang province during the study period. At the provincial level, temperature that corresponding to the lowest risk of OID was 16.7 ℃, and the temperature corresponding to the highest risk was 6.2℃ (RR=2.298, 95%CI: 1.527- 3.459). 16.7 ℃ was recognized as the reference temperature. P(5) and P(95) of the average daily temperature represented low and high temperature respectively. When the temperature was cold, the risk was delayed by 2 days, with the highest risk found on the 5(th) day (RR=1.057, 95%CI: 1.030-1.084) before decreasing to the 23(rd) day. When the temperature got hot, the risk of OID occurred on the first day (RR=1.081, 95%CI: 1.045-1.118) and gradually decreasing to the 8(th) day. Differences on heterogeneous sources related to the risks of OID in different regions, presented on urban latitude and the rate of ageing in the population. Conclusions: Both high or low temperature could increase the risk of OID, with a lag effect noticed. Prevention program on OID should be focusing on populations living in the high latitude and the elderly population at the low temperature areas.


Assuntos
Temperatura Baixa , Diarreia/epidemiologia , Disenteria/epidemiologia , Temperatura Alta , Idoso , China , Diarreia/diagnóstico , Disenteria/diagnóstico , Humanos , Temperatura Ambiente
3.
J Agric Food Chem ; 67(38): 10734-10743, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31479252

RESUMO

Glutenin is the main protein of flour and is a very important source of protein nutrition for humans. Methylglyoxal (MGO) is an important product of the Maillard reaction that occurs during the hot-processing of flour products, and it reacts with glutenin to facilitate changes in glutenin properties. Here, the effects of MGO on glutenin digestion during the heating process were investigated using a simulated MGO-glutenin system. MGO significantly reduced the digestibility of glutenin. The structure of MGO-glutenin and physicochemical properties were studied to understand the mechanism of the decrease of digestibility. These data suggest that changes in digestibility were caused by decreases in surface hydrophobicity and increases in disulfide bonds. MGO induces strong aggregation of glutenin after heating that led to the masking of cleavage sites for proteases. Moreover, carbonyl oxidation induced by MGO leads to intermolecular cross-linking of glutenin that increasingly masks or even destroys cleavage sites, further decreasing digestibility.


Assuntos
Glutens/química , Aldeído Pirúvico/química , Culinária , Digestão , Farinha/análise , Glutens/metabolismo , Temperatura Alta , Humanos , Interações Hidrofóbicas e Hidrofílicas , Reação de Maillard , Oxirredução , Aldeído Pirúvico/metabolismo
4.
Microb Cell Fact ; 18(1): 159, 2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31542050

RESUMO

BACKGROUND: Xylanases randomly cleave the internal ß-1,4-glycosidic bonds in the xylan backbone and are grouped into different families in the carbohydrate-active enzyme (CAZy) database. Although multiple xylanases are detected in single strains of many filamentous fungi, no study has been reported on the composition, synergistic effect, and mode of action in a complete set of xylanases secreted by the same microorganism. RESULTS: All three xylanases secreted by Penicillium chrysogenum P33 were expressed and characterized. The enzymes Xyl1 and Xyl3 belong to the GH10 family and Xyl3 contains a CBM1 domain at its C-terminal, whereas Xyl2 belongs to the GH11 family. The optimal temperature/pH values were 35 °C/6.0, 50 °C/5.0 and 55 °C/6.0 for Xyl1, Xyl2, and Xyl3, respectively. The three xylanases exhibited synergistic effects, with the maximum synergy observed between Xyl3 and Xyl2, which are from different families. The synergy between xylanases could also improve the hydrolysis of cellulase (C), with the maximum amount of reducing sugars (5.68 mg/mL) observed using the combination of C + Xyl2 + Xyl3. Although the enzymatic activity of Xyl1 toward xylan was low, it was shown to be capable of hydrolyzing xylooligosaccharides into xylose. Xyl2 was shown to hydrolyze xylan to long-chain xylooligosaccharides, whereas Xyl3 hydrolyzed xylan to xylooligosaccharides with a lower degree of polymerization. CONCLUSIONS: Synergistic effect exists among different xylanases, and it was higher between xylanases from different families. The cooperation of hydrolysis modes comprised the primary mechanism for the observed synergy between different xylanases. This study demonstrated, for the first time, that the hydrolysates of GH11 xylanases can be further hydrolyzed by GH10 xylanases, but not vice versa.


Assuntos
Endo-1,4-beta-Xilanases/metabolismo , Proteínas Fúngicas/metabolismo , Penicillium chrysogenum/enzimologia , Polissacarídeos/metabolismo , Biocatálise , Endo-1,4-beta-Xilanases/química , Endo-1,4-beta-Xilanases/genética , Estabilidade Enzimática , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Glucuronatos/metabolismo , Temperatura Alta , Hidrólise , Família Multigênica , Oligossacarídeos/metabolismo , Penicillium chrysogenum/química , Penicillium chrysogenum/genética , Domínios Proteicos , Xilanos/metabolismo
5.
Waste Manag ; 99: 146-153, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31476639

RESUMO

The thermal degradation dynamics of new and aged PVC sheaths was studied in detail. The results illustrated that compared to new PVC sheath, the onset decomposition of aged PVC sheath mainly happened at higher temperature with larger peak value of mass loss rate. Three model-free methods most commonly used were employed to estimate the activation energy values at different conversions. It was noted that the aged PVC sheath exhibited greater entire activation energy than new PVC sheath. Two thermal degradation regions were observed based on the activation energy variation with conversion. The threshold of conversion for two regions was 0.6 for new PVC sheath and 0.5 for aged PVC sheath. The possible reaction mechanism was predicted by generalized master-plots method. The reaction model corresponding to each region showed observed difference between new and aged PVC sheaths. The compensation effect was also used to calculate the related pre-exponential factor. The variation of thermal degradation behavior could be ascribed to the changes of chemical composition, molecular structure, composition proportion and various additives after thermal aging. Besides, the thermal degradation process was reconstructed by an ANN model and it indicated that the predicted data fitted well with the experimental data.


Assuntos
Temperatura Alta , Cloreto de Polivinila , Cinética
6.
Bioresour Technol ; 291: 121860, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31374414

RESUMO

This study aims to enhance the quality of biofuel through microwave torrefaction pretreatment for lignin. Low density polyethylene (LDPE) was added as a hydrogen source during microwave co-pyrolysis along with the microwave-torrefied lignin (MTL). The thermal degradation behavior and kinetic study of MTL co-pyrolysis with LDPE by microwave-assisted heating was investigated as well. The results indicated that the hydrocarbon content in the bio-oil obtained from microwave co-pyrolysis of MTL and LDPE increased significantly (about 80%). It was also noticed that the aromatic hydrocarbon content increased from 1.94% to 22.83% with the addition of LDPE. Thermal behavior analysis and reaction kinetic study showed that the addition of LDPE into MTL had the effect of promoting thermal degradation and improving reaction rate during microwave-assisted pyrolysis.


Assuntos
Hidrocarbonetos/química , Lignina/química , Óleos Vegetais/química , Polietileno/química , Polifenóis/química , Temperatura Alta , Cinética , Micro-Ondas , Pirólise
7.
Bioresour Technol ; 291: 121842, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31377505

RESUMO

The spherical cellulose nanocrystals (CNCs) with high purity were prepared, the processes included composite enzymolysis of pulp fibers and the purification of product. The impurities in the crude product CNCs were analyzed with FTIR, coomassie brilliant blue-G250 and ionic chromatography. The pure CNCs were characterized with SEM, XRD, DLS and TGA. The results indicated that the crude CNCs was flocculated and washed twice with a dilute acid solution (pH = 2) to get pure spherical CNCs, the purity was approximate 99.99%. The obtained pure spherical CNCs had a narrow particle size distribution with diameter 15-40 nm. FTIR and XRD analyses proved that the crystal phase of the spherical CNCs did not change, but the crystallinity decreased slightly compared with pulp fibers. The thermal degradation showed that the spherical CNCs had better thermal stability than one from other methods, and the temperature of maximum weight loss rate (Tmax) was 329.2 °C.


Assuntos
Celulose/química , Nanopartículas/química , Temperatura Alta , Papel , Espectroscopia de Infravermelho com Transformada de Fourier
9.
Sud Med Ekspert ; 62(4): 14-18, 2019.
Artigo em Russo | MEDLINE | ID: mdl-31407700

RESUMO

The purpose of the work is to study the possibility of using carbon nanotubes (CNT) as taggants in gun powder to provide expert differentiation of used small firearms cartridges; and to identify the main characteristics of the changes to carbon nanotubes under firing conditions, i.e. short-term exposure to high temperatures and pressures. The principal possibility of using carbon nanotube material for marking gunpowder in small firearms cartridges is stated. There is a need, in both the theory and practice of forensics, to develop such a labeling additive, one that is designed to analyze labeled cartridges and trace their use. We studied the effect of high temperatures and pressures (up to 3000-3500 ºC, 30 MPa) on the behavior of carbon nanotubes by using scanning electron microscopy. We found that the properties of carbon nanotube material - including high chemical and thermal resistance, low prevalence in nature, and a wide variety of forms and configurations - would help solve various investigative issues related to the circumstances of the use of small firearms, in particular, to determine the batch or sample of gunpowder used in the firing of a cartridge.


Assuntos
Armas de Fogo , Balística Forense/métodos , Nanotubos de Carbono , Temperatura Alta , Microscopia Eletrônica de Varredura , Pressão
10.
World J Microbiol Biotechnol ; 35(8): 126, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31363938

RESUMO

Isolation and identification of temperature tolerant phosphate solubilizing bacteria (TTPSB) and their use as microbial fertilizers was the main goal of the study. In this study, TTPSB were isolated from soil samples treated for 16 h at 55 °C. Their phosphate solubilizing activity was either evaluated in solid media by forming a clear zone (halo) or in liquid media by quantification of the soluble phosphate in the growth medium. Five colonies (RPS4, RPS6, RPS7, RPS8 and RPS9) were identified to be able to form a halo and two of the isolates (RPS9 and RPS7) tolerated a temperature of 55 °C. With tricalcium phosphate (TCP) as the sole P-source, the phosphate solubilizing capacity of RPS9 and RPS7 was determined to be 563.8 and 324.1 mg P L-1 in liquid Sperber medium, respectively. Both bacterial isolates were identified as Pantoea agglomerans by molecular and biochemical characterization. To be used as a microbial fertilizer a carrier system for the temperature tolerant bacteria consisting of rock phosphate, sulfur and bagasse was used. It could be established that the bacterial cell counts of the microbial fertilizers were acceptable for application after storage for 4 months at 28 °C. In a greenhouse experiment using pot cultures, inoculation of maize (S.C.704) with the microbial fertilizers in an autoclaved soil resulted in a significant effect on total fresh and dry weight of the plant root and shoot as well as on the P content of the root and shoot. The effects observed with RPS9 as a component of the microbial fertilizer on plant growth and P nutrition was comparable with the addition of 50% of recommended triple superphosphate (TSP) dose. Using temperature tolerant bacteria in microbial fertilizers will overcome limitations in production and storage of the microbial fertilizers and contribute to a environmentally-friendly agriculture. The temperature tolerant P. agglomerans strain RPS9 was shown to be effective as part of a microbial fertilizer in supporting the growth and P uptake in maize.


Assuntos
Agricultura/métodos , Fosfatos de Cálcio/metabolismo , Pantoea/isolamento & purificação , Pantoea/metabolismo , Microbiologia do Solo , Zea mays/crescimento & desenvolvimento , Técnicas Bacteriológicas , Biotransformação , Fosfatos de Cálcio/química , Meios de Cultura/química , Temperatura Alta , Pantoea/classificação , Pantoea/efeitos da radiação , Solubilidade , Zea mays/microbiologia
11.
J Appl Oral Sci ; 27: e20180689, 2019 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-31411264

RESUMO

OBJECTIVE: The aim of this study was to evaluate the root canal preparation and apical enlargement of molar root canals with rotary or reciprocating heat-treated nickel-titanium (NiTi) instruments, by using micro-computed tomography (micro-CT). METHODOLOGY: Mesial root canals (n=48) of mandibular molars, with a curvature between 20° and 40°, were prepared with ProDesign Logic (PDL) 25.01 and 25.06 in rotary motion, or ProDesign R (PDR) 25.06 in reciprocating motion (PDR). Apical enlargement was performed with PDL35.01 and PDL35.05 or PDR35.05. Scanning with 9 µm resolution was performed before and after preparation, and, after apical enlargement, by using micro-CT. The percentage of volume increase, debris and untouched root canal surface, transportation, centralization and preparation time were analyzed. ANOVA and Tukey or Kruskall-Wallis and Dunn statistical tests were conducted (α=.05). RESULTS: PDL promoted a higher apical percentage of volume increase, and lower percentage of debris and untouched root canal surface than PDR 25.06 preparation in entire canal and in all thirds (P<.05). Apical enlargement with PDL 35.05 and PDR 35.05 produced a higher percentage of volume increase in the apical region in relation to the initial preparation (P<.05). PDR 35.05 and PDL 35.05 showed similar results in relation to percentage of debris and untouched root canal surface in entire canal and in all thirds (P>.05). Centralization and transportation showed no difference (P>.05). PDR required less time to perform preparation and apical enlargement (P<.05). CONCLUSIONS: The apical enlargement 35.05 with CM heat-treatment instruments using reciprocating and rotary motion reduced the percentage of debris and untouched root canal surface, without causing deviations or procedural errors. The protocol of greater apical enlargement favors the cleaning of the root canals in both kinematics. Preparation by the reciprocating system was faster than by the rotary system.


Assuntos
Instrumentos Odontológicos , Cavidade Pulpar/diagnóstico por imagem , Níquel , Preparo de Canal Radicular/instrumentação , Titânio , Análise de Variância , Cavidade Pulpar/anatomia & histologia , Desenho de Equipamento , Temperatura Alta , Humanos , Teste de Materiais , Valores de Referência , Reprodutibilidade dos Testes , Estatísticas não Paramétricas , Propriedades de Superfície , Microtomografia por Raio-X
12.
Zhen Ci Yan Jiu ; 44(7): 520-4, 2019 Jul 25.
Artigo em Chinês | MEDLINE | ID: mdl-31368285

RESUMO

The quantity of mild moxibustion stimulation is an important factor affecting clinical therapeutic effect. In the present study, we collected related literature by using key word "moxibustion stimulation quantity" from CNKI Database and make a summary about its concept. The quantity of mild moxibustion stimulation has two common characters, namely thermal intensity and cumulative stimulating quantity, and contains 6 components (parameters), including thermal energy, thermal stimulus, heated area of the skin, and stimulating duration, intensity and frequency. According to the facts mentioned above, we hold that the mild moxibustion quantity actually has 3 dimensions, i.e., the duration of stimulation, the stimulating quantity of one treatment session, and the total stimulating quantity of multiple treatment sessions. Accurately grasping and rationally using the basic term of the quantity of mild moxibustion is not only conductive to control clinical moxibustion operation, but also conforms to the basic requirements for quantitative control of intervention measures in experimental researches.


Assuntos
Moxibustão , Pontos de Acupuntura , Bases de Dados Factuais , Temperatura Alta
13.
Oecologia ; 191(1): 205-215, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31420741

RESUMO

Avian responses to high environmental temperatures include retreating to cooler microsites and/or increasing rates of evaporative heat dissipation via panting, both of which may affect foraging success. We hypothesized that behavioural trade-offs constrain the maintenance of avian body condition in hot environments, and tested predictions arising from this hypothesis for male Southern Yellow-billed Hornbills (Tockus leucomelas) breeding in the Kalahari Desert. Operative temperatures experienced by the hornbills varied by up to 13 °C among four microsite categories used by foraging males. Lower prey capture rates while panting and reductions associated with the occupancy of off-ground microsites, resulted in sharp declines in foraging efficiency during hot weather. Consequently, male body mass (Mb) gain between sunrise and sunset decreased with increasing daily maximum air temperature (Tmax), from ~ 5% when Tmax < 25 °C to zero when Tmax = 38.4 °C. Overnight Mb loss averaged ~ 4.5% irrespective of Tmax, creating a situation where nett 24-h Mb loss approached 5% on extremely hot days. These findings support the notion that temperature is a major determinant of body condition for arid-zone birds. Moreover, the strong temperature dependence of foraging success and body condition among male hornbills provisioning nests raises the possibility that male behavioural trade-offs translate into equally strong effects of hot weather on female condition and nest success. Our results also reveal how rapid anthropogenic climate change is likely to substantially decrease the probability of arid-zone birds like hornbills being able to successfully provision nests while maintaining their own condition.


Assuntos
Aves , Regulação da Temperatura Corporal , Animais , Temperatura Baixa , Feminino , Temperatura Alta , Masculino , Temperatura Ambiente
14.
Adv Exp Med Biol ; 1155: 1049-1056, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31468466

RESUMO

This study investigated the effects of taurine on bowel inflammation resulting from heat stress in broilers, with the intent of providing insight into potential improvement of the condition of broilers. A total of 300 healthy 1 day AA broilers were selected, fed normally until day 7, and allocated randomly to 5 treatment groups, namely, the control group(C), the heat stress group(HS), the low Tau (LTau) group, the middle Tau (MTau) group and the high Tau (HTau) group, which represent low, medium and high concentrations of taurine respectively. In the study, various concentrations of taurine were added to the drinking water. The Heat Stress model was produced by maintaining Broilers in a room at 34 °C.Heat stress persisted for 6 h, 12 h, 7 days, and 14 days. The results showed that the expression levels of TNF-α, IFN-γ, and IL-1ß of the HTau group were significantly lower than that of the HS group at all time points examined (6 h, 12 h, 7 days, and 14 days) (P < 0.05). Compared with the HS group subjected to 6 h, 12 h and 14 days of heat stress, the MTau group exhibited significantly lower degrees of TNF-α and IL-1ß expression. Moreover, the expression of IFN-γ was higher in the HS group after 6 h, 12 h and 7 days of heat stress than that of the MTau group subjected to similar times of heat stress (P < 0.05).There were no significant difference among the groups at other periods of heat stress (P > 0.05).


Assuntos
Resposta ao Choque Térmico , Mucosa Intestinal/efeitos dos fármacos , Intestino Delgado/efeitos dos fármacos , Taurina/farmacologia , Animais , Galinhas , Citocinas/metabolismo , Temperatura Alta , Distribuição Aleatória
15.
J Agric Food Chem ; 67(37): 10401-10411, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31441654

RESUMO

This research applied inhibitors to reduce the content of cooked off-flavor components (dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, and 3-(methylthio)propanaldehyde) in heat-treated melon juice. The effects of glucose oxidase (GOD) on the formation and release of these four volatile sulfur compounds were also investigated. Results showed that GOD strongly inhibited the formation of the four compounds. In GOD-treated melon juice, S-methylmethionine was strongly protonated and not easily degraded into dimethyl sulfide. Moreover, the release of the dimethyl sulfide that did form was restrained by the hydrophobic interactions of gluconic acid and oxidation by hydrogen peroxide. In addition, gluconic acid (or glucose) and hydrogen peroxide could form a stable complex with methionine in an acidic matrix and thus prevented the methionine from producing 3-(methylthio)propanaldehyde, dimethyl disulfide, and dimethyl trisulfide by the Maillard reaction during heat processing.


Assuntos
Cucurbitaceae/química , Aromatizantes/química , Sucos de Frutas e Vegetais/análise , Culinária , Cucurbitaceae/enzimologia , Frutas/química , Frutas/enzimologia , Glucose Oxidase/química , Temperatura Alta , Humanos , Reação de Maillard , Odorantes/análise , Proteínas de Plantas/química , Compostos de Enxofre/química , Paladar
16.
J Agric Food Chem ; 67(37): 10373-10379, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31453692

RESUMO

Agarose can be hydrolyzed into agarooligosaccharides (AOSs) by α-agarase, which is an important enzyme for efficient saccharification of agarose or preparation of bioactive oligosaccharides from agarose. Although many ß-agarases have been reported and characterized, there are only a few studies on α-agarases. Here, we cloned a novel α-agarase named CaLJ96 with a molecular weight of approximately 200 kDa belonging to glycoside hydrolase family 96 from Catenovulum agarivorans. CaLJ96 has good pH stability and exhibits maximum activity at 37 °C and pH 7.0. The hydrolyzed products of agarose by CaLJ96 are analyzed as agarobiose (A2), agarotetraose (A4), and agarohexaose (A6), in which A4 is the dominant product. CaLJ96 can hydrolyze agaropentaose (A5) into A2 and agarotriose (A3) and A6 into A2 and A4 but cannot act on A2, A3, or A4. This is the first report to characterize the α-agarase action on AOSs in detail. Therefore, CaLJ96 has potential for the manufacture of bioactive AOSs.


Assuntos
Alteromonadaceae/enzimologia , Proteínas de Bactérias/química , Glicosídeo Hidrolases/química , Alteromonadaceae/química , Alteromonadaceae/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Clonagem Molecular , Estabilidade Enzimática , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Temperatura Alta , Concentração de Íons de Hidrogênio , Peso Molecular , Oligossacarídeos/química , Oligossacarídeos/metabolismo , Sefarose/química , Sefarose/metabolismo , Especificidade por Substrato
17.
J Agric Food Chem ; 67(37): 10505-10512, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31462045

RESUMO

An aspartic protease gene (Bsapa) was cloned from Bispora sp. MEY-1 and expressed in Pichia pastoris. The recombinant BsAPA showed maximal activity at pH 3.0 and 75 °C and remained stable at 70 °C and below, indicating the thermostable nature of BsAPA. However, heat inactivation still limits the application of BsAPA. To further improve its thermostability, an autocatalysis site (L205-F206) in BsAPA was identified and three mutants (F193W, K204P, and A371V) were generated based on the analysis of the structure neighboring the autocatalysis site. These mutants have improved thermostability, and their half-life at 75 °C increased by 0.5-, 0.2-, and 0.3-fold, respectively. A triple-site mutant (F193W/K204P/A371V) was generated, with 1.5-fold increased half-life at 80 and a 10.7 °C increased Tm, compared with those of the wild-type. These results indicate that autocatalysis of aspartic protease reduces enzyme thermostability. Furthermore, site-directed mutagenesis at regions near the autocatalysis site is an efficient approach to improve aspartic protease thermostability.


Assuntos
Ascomicetos/enzimologia , Ácido Aspártico Proteases/química , Ácido Aspártico Proteases/genética , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Ascomicetos/química , Ascomicetos/genética , Ácido Aspártico Proteases/metabolismo , Estabilidade Enzimática , Proteínas Fúngicas/metabolismo , Temperatura Alta , Cinética , Mutagênese Sítio-Dirigida , Mutação , Pichia/genética , Pichia/metabolismo
18.
J Agric Food Chem ; 67(37): 10470-10480, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31469565

RESUMO

Foodborne nanoparticles (FNPs) produced by roasting have attracted the attention of people, owing to their safety risk to body health. Herein, we reported the formation, physicochemical properties, elemental composition, biodistribution, and binding with human serum albumin (HSA) of FNPs extracted from roast squid. The results showed that the FNP size gradually decreased from 4.1 to 2.3 nm as the roasting temperature changed from 190 to 250 °C. The main component elements of FNPs are carbon, oxygen, and nitrogen, and the carbon and nitrogen contents of FNPs increased with the roasting temperature rising. The surface of FNPs contained hydroxyl, amino, and carboxyl functional groups. The FNPs can emit fluorescence in ultraviolet light and show excitation-dependent emission behavior. Furthermore, it was found that the FNPs derived from roast squid could be accumulated in the stomach, intestine, and brain of BALB/c mice after oral feeding. Static fluorescence quenching of HSA was found by the Stern-Volmer equation and ultraviolet-visible spectrum analysis after interaction with the FNPs. After the addition of FNPs, the α-helix content of HSA decreased and the morphological height of HSA increased, which indicated that the FNPs could cause structural changes in HSA. The atomic force microscopy characterization showed the formation of nanocorona between FNPs and HSA.


Assuntos
Decapodiformes/química , Nanopartículas/química , Nanopartículas/metabolismo , Albumina Sérica Humana/química , Animais , Culinária , Decapodiformes/metabolismo , Fluorescência , Temperatura Alta , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Microscopia de Força Atômica , Tamanho da Partícula , Ligação Proteica , Conformação Proteica , Albumina Sérica Humana/metabolismo , Distribuição Tecidual
19.
Vet Parasitol ; 272: 64-74, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31395207

RESUMO

This study aimed to evaluate the mite fauna and their ecological interactions in commercial laying hen farms in the state of Rio Grande do Sul, Brazil. It was conducted from August 2013 through August 2014 with two sampling strategies (feathers and traps) in three different production systems: automated (A1,2,3), semi-automated (S1,2) and free-range (FR). A total of 38,383 mites were collected belonging to 23 families and 33 species, most of which were collected in feathers (74%) followed by traps (26%). There was higher abundance at S1 (10,774-28.1%) and S2 (11,023-28.7%) followed by FR (6972-18.2%), A1 (1896-4.9%), A2 (4775-12.4%), and A3 (2943-7.7%). Higher richness was observed at S1 (23 species), S2 (18 species), and FR (19 species). Megninia ginglymura (Mégnin) (Analgidae) was the species with the highest health importance, eudominant on feathers, and its populations seems to be related with increased temperature. Tuccioglyphus setosus Horn et al. (Pyroglyphidae) seems to be influenced by relative air humidity and temperature. Predators with the highest populations were Cheyletus malaccensis (Oudemans) (Cheyletidae), Typhlodromus transvaalensis (Nesbitt) (Phytoseiidae), Blattisocius keegani (Fox), and Blattisocius dentriticus (Berlese) (Blattisocidae).


Assuntos
Infestações por Ácaros/veterinária , Ácaros/fisiologia , Doenças das Aves Domésticas/parasitologia , Criação de Animais Domésticos , Animais , Biodiversidade , Brasil , Galinhas , Feminino , Temperatura Alta , Umidade , Infestações por Ácaros/parasitologia , Ácaros/classificação , Controle Biológico de Vetores , Dinâmica Populacional , Fatores de Risco
20.
Bioresour Technol ; 292: 121893, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31430669

RESUMO

A process model based on hot water extraction (HWE), slow pyrolysis and anaerobic digestion (AD) were used for pine and spruce bark utilisation. First tannins (32 mg/g and 11.8 mg/g, respectively) and polyphenols were recovered via HWE. Then, the residue was pyrolysed to produce biochar (marketable quality), gas (energy source) and liquid fractions. The liquid fraction was further separated into aqueous acidic fraction and to tar fraction. Bark, extracted bark residue and acidic liquid fraction from pyrolysis were treated in AD to produce biomethane and digestate. The methane yields from pine and spruce bark and extracted bark residue were low (from 42 to 96 mLCH4/gVSadded) and showed only small differences. In conclusion, cascade processing can improve the performance of subsequent single processes and utilise biomass sources with higher efficiency. The best processing chain may vary in different cases and the overall energy balance of processing needs further research.


Assuntos
Temperatura Alta , Pirólise , Anaerobiose , Casca de Planta , Água
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