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1.
Cell Transplant ; 33: 9636897241236584, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38501500

RESUMO

Aging, space flight, and prolonged bed rest have all been linked to bone loss, and no effective treatments are clinically available at present. Here, with the rodent hindlimb unloading (HU) model, we report that the bone marrow (BM) microenvironment was significantly altered, with an increased number of myeloid cells and elevated inflammatory cytokines. In such inflammatory BM, the osteoclast-mediated bone resorption was greatly enhanced, leading to a shifted bone remodeling balance that ultimately ends up with disuse-induced osteoporosis. Using Piezo1 conditional knockout (KO) mice (Piezo1fl/fl;LepRCre), we proved that lack of mechanical stimuli on LepR+ mesenchymal stem cells (MSCs) is the main reason for the pathological BM inflammation. Mechanically, the secretome of MSCs was regulated by mechanical stimuli. Inadequate mechanical load leads to increased production of inflammatory cytokines, such as interleukin (IL)-1α, IL-6, macrophage colony-stimulating factor 1 (M-CSF-1), and so on, which promotes monocyte proliferation and osteoclastic differentiation. Interestingly, transplantation of 10% cyclic mechanical stretch (CMS)-treated MSCs into HU animals significantly alleviated the BM microenvironment and rebalanced bone remodeling. In summary, our research revealed a new mechanism underlying mechanical unloading-induced bone loss and suggested a novel stem cell-based therapy to potentially prevent disuse-induced osteoporosis.


Assuntos
Reabsorção Óssea , Osteoporose , Camundongos , Animais , Secretoma , Reabsorção Óssea/patologia , Camundongos Knockout , Inflamação , Citocinas , Canais Iônicos
2.
Appl Microbiol Biotechnol ; 108(1): 260, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38472422

RESUMO

Staphylococcus aureus is associated with dairy mastitis, which causes serious economic losses to dairy farming industry. Antibacterial peptide NZX showed good antibacterial activity against S. aureus. This study aimed to evaluate pharmacokinetics and pharmacodynamics of NZX against S. aureus-induced mouse mastitis. NZX exhibited potent in vitro antibacterial activity against the test S. aureus strains (minimal inhibitory concentration (MIC): 0.23-0.46 µM), low mutant prevention concentration (MPC: 1.18-3.68 µM), and a long post antibiotic effect (PAE: 2.20-8.84 h), which was superior to those of lincomycin and ceftiofur. Antibacterial mechanisms showed that NZX could penetrate the cell membrane, resulting in obvious cell membrane perforation and morphological changes, and bind to intracellular DNA. Furthermore, NZX had a good stability in milk environment (retention rate: 85.36%, 24 h) than that in mammary homogenate (47.90%, 24 h). In mouse mastitis model, NZX (25-400 µg/gland) could significantly reduce the bacterial load of mammary tissue in a dose-dependent manner. In addition, NZX (100 µg/gland) could relieve the inflammatory symptoms of mammary tissue, and significantly decreased its pathological scores. The concentration-time curve of NZX (100 µg/gland) in the mammary tissue was plotted and the corresponding pharmacokinetic parameters were obtained by non-compartment model calculation. Those parameters of Tmax, T1/2, Cmax and AUC were 0.5 h, 35.11 h, 32.49 µg/g and 391 µg·h/g, respectively. Therefore, these results suggest that NZX could act as a promising candidate for treating dairy mastitis disease caused by S. aureus. KEY POINTS: • NZX could kill S. aureus by dual mechanism involved in membrane and DNA disruption • NZX could relieve S. aureus-induced mouse mastitis • Pharmacokinetic parameters of NZX in mouse mammary gland were obtained.


Assuntos
Mastite Bovina , Infecções Estafilocócicas , Feminino , Camundongos , Animais , Bovinos , Humanos , Staphylococcus aureus , Antibacterianos/farmacologia , Infecções Estafilocócicas/tratamento farmacológico , Modelos Animais de Doenças , Peptídeos Catiônicos Antimicrobianos/farmacologia , Mastite Bovina/microbiologia , DNA/metabolismo
3.
Int J Biol Macromol ; 262(Pt 1): 129993, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38325684

RESUMO

Fermentation plays a crucial role in traditional Chinese mianpi processing, where short-term natural fermentation (within 24 h) is considered advantageous for mianpi production. However, the influence of short-term natural fermentation on the properties of wheat starch is not explored yet. Hence, structural characteristics and paste properties of wheat starch during natural fermentation were investigated in this study. The findings revealed that fermenting for 24 h had a slight effect on the morphology of wheat starch but significantly decreased the particle size of starch. Compared to native wheat starch, the enzyme activity produced during fermentation may destroy the integrity of starch granules, resulting in a lower molecular weight but higher relative crystallinity and orderliness of starch. After 24 h of natural fermentation, higher solubility and swelling power were obtained compared to non-fermentation. Regarding paste properties, fermented starches exhibited higher peak viscosity and breakdown, along with lower final viscosity, tough viscosity, and setback. Furthermore, the hardness, gel strength, G', and G" decreased after fermentation. Clarifying changes in starch during the short-term natural fermentation process could provide theoretical guidance for improving the quality and production of short-term naturally fermented foods such as mianpi, as discussed in this study.


Assuntos
Amido , Triticum , Amido/química , Triticum/química , Fermentação , Viscosidade , China
4.
Food Funct ; 15(6): 3108-3121, 2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38421019

RESUMO

Pre-meal immersion is a common process for both the consumption of dried noodles and development of takeaway noodles, but its impact on the structure and digestibility of dried noodles is still unclear. In this study, dried noodles cooked for the optimal time were immersed at 80 °C for different time durations. Multi-scale structural changes, including texture, molecular structure, microstructure, and in vitro starch digestibility were studied using a combination of kinetic (first-order exponential decay function, the Peleg model, and LOS plots), physicochemical, and microscopic analysis. The relationship between multi-scale structural changes and starch digestibility was derived. As the immersion progressed, the hardness first rapidly decayed and then reached equilibrium. The decay rate in the initial stage depended on the gluten content. In most cases, the immersion process caused depolymerization of gluten proteins and further gelatinization of starch granules, which was observed from an increase in the free -SH content and decrease in the short-range ordered structure, although there were fluctuations over immersion time. Structural changes resulted in the corresponding changes in substance migration. However, a high gluten content (∼15% w/w) imparted a denser microstructure to the noodles, weakening the deterioration effects compared with a low gluten content (∼10% w/w). In vitro digestion experiments proved that samples with higher gluten content had higher starch digestion rates and lower starch digestion extent during immersion. Correlation analysis revealed that there was a negative correlation between k1 and the tightness of the gel. This study helps to reveal the structural mechanisms of starch digestibility in cooked noodles during immersion.


Assuntos
Imersão , Amido , Amido/química , Culinária , Glutens , Farinha/análise
5.
J Food Sci ; 89(1): 306-319, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38018239

RESUMO

Comparative studies were conducted on physicochemical and technological properties of two black wheat (BW) varieties (cultivated in Shanxi Agricultural University) and their noodle-making potential. Whole-grain BW noodles showed acceptable cooking loss (≤10%) and strong antioxidant capacity. However, their textural quality remains to be enhanced. Regarding refined flour (RF) of the two BW varieties, Yunhei 14207 showed more anthocyanins, brighter color, and greater thermal stability (as reflected by the higher pasting temperature). 16W16 resulted in greater gluten content and better gluten quality of flour and higher dough stability, which contributed to the lower cooking loss and stronger tensile property of noodles. RF noodles of Yunhei 14207 displayed brighter appearance, although they had weaker tensile property. The stronger gluten network in noodles of 16W16 protected phenolics from release and degradation during drying, cooking, and steaming. Despite phenolics loss, RF noodles of Yunhei 14207 showed antioxidant capacity up to 14.97 mg TE/100 g. This research would promote understanding of characteristics of BW varieties. Considering the stronger gluten network of 16W16, its fortification in common wheat noodles at high proportion (>50%) may be promising to develop antioxidant noodles with further improved sensory quality.


Assuntos
Farinha , Triticum , Humanos , Farinha/análise , Triticum/química , Antioxidantes , Antocianinas , Culinária , Glutens/química
6.
Ann Hematol ; 103(3): 729-736, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38151521

RESUMO

Hematologic diseases and various therapeutic stages can impact the presentation of SARS-CoV-2 Omicron variant infection. This study retrospectively analyzed data on Omicron infection in children with acute leukemia treated at our hospital between January 16, 2023, and February 25, 2023, using questionnaires. The prevalence of Omicron infection in children undergoing consolidation chemotherapy, maintenance chemotherapy, drug withdrawal, and healthy children was 81.8%, 75.2%, 55.2%, and 61.9%, respectively. The observed differences were statistically significant (P < 0.05). During the course of infection, children with leukemia undergoing chemotherapy, including both the consolidation and maintenance chemotherapy groups, exhibited a prolonged time to achieve SARS-CoV-2 negativity compared to the drug withdrawal and healthy groups. However, there was no significant increase in the incidence of symptoms across all body systems, and no children experienced serious sequelae or death. Furthermore, our observations indicated that all manifestations of Omicron infection in children with leukemia after drug withdrawal were not significantly different from those in healthy children. This suggested, to a certain extent, that the immune function of children with leukemia recovers effectively after the cessation of drug treatment. These findings are crucial for guiding clinical management and alleviating concerns about infection for both children with leukemia and their parents.


Assuntos
COVID-19 , Leucemia Mieloide Aguda , Criança , Humanos , SARS-CoV-2 , Estudos Retrospectivos , COVID-19/complicações , Leucemia Mieloide Aguda/complicações , Leucemia Mieloide Aguda/tratamento farmacológico
7.
Food Chem X ; 20: 100927, 2023 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-38144810

RESUMO

The effects of freeze-thawed cycles (FTs) and a new antifreeze protein from Sabina chinensis (Linn.) Ant. cv. Kaizuca leaves (ScAFP) on the structure and physicochemical characteristics of wheat starch were studied. The mechanical breaking exerted by ice crystals on starch granules during FTs gradually deepened, sequentially squeezing the surface (2-6 FTs), amorphous region (8 FTs) and crystalline region (10 FTs) of starch granules. These changes led to reduced thermal stability, increased retrogradation tendency, and weakened gel network structure. The addition of ScAFP retarded the damage of ice crystals on starch granule structure and crystal structure during FTs, and significantly reduced the retrogradation tendency. Compared with native starch, the hardness of freeze-thawed starch without and with added ScAFP after 10 FTs decreased by 17.85% and 9.22%, respectively, indicating ScAFP improved the gel texture properties of freeze-thawed starch. This study provides new strategies for improving the quality of frozen starch-based foods.

9.
J Dairy Sci ; 106(11): 7329-7335, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37641347

RESUMO

Lactoferrin is an iron-binding glycoprotein of the transferrin family that is found in most bodily fluids of mammals and has a variety of biological and beneficial functions, with great importance in health enhancement as a supplement for humans and other animals. More than 300 t of lactoferrin were produced in 2021, and this number is expected to grow yearly by 10% to 12%, to over 580 t in 2030. With new and important functions of lactoferrin being revealed and studied, focus on its industrial production and application is increasing accordingly. However, lactoferrin is mainly sourced from cheese whey or skim milk by cation-exchange column chromatography, which is a costly and low-quality method. A potential solution for lactoferrin global supply chain construction is proposed in this article as a complement to traditional routes of purification from whey or skim milk. The large-scale production of lactoferrin, mainly by recombinant yeast, mammal, and grain systems, as well as the market niche and product design, are discussed.

10.
Food Funct ; 14(15): 6784-6801, 2023 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-37455581

RESUMO

Nutritional and epidemiological studies suggest that the excessive intake of highly processed starchy foods contributes to the risk of type II diabetes and obesity in consumers. This is partly caused by the disruption of the cellular structure of cereal endosperms or legume cotyledons in foods during processing, which releases large amounts of highly digestible starch though the cell wall structure. Thus, to improve the production of starch-based foods with slowly digestible starch, it is necessary to clarify the influence of the structural integrity of cereal endosperm and legume cotyledon cells and the modification of their structure during processing on the starch digestion properties. However, the effect of mechanical, chemical, biological, or enzymatic modification of the cell wall during the processing of cereals and legumes on the digestive properties of starch has not been summarized well. Accordingly, in the present review, we fill this gap by summarizing the biophysical properties of common cereal and legume endosperm/cotyledon cells. Furthermore, we elaborate on the mechanisms involved in imparting cell wall integrity and controlling the starch digestion properties. Subsequently, the starch release pattern after cell wall modification is also discussed. In addition, a new classification system is proposed, which is beneficial for conducting cell research. This review provides new insights into the cell wall integrity of starch sources and the effect of the modification of cereal and legumes on starch digestion, which will benefit the scientific community and industry.

11.
Int J Biol Macromol ; 248: 125956, 2023 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-37487993

RESUMO

Polysaccharide-based hydrocolloids (PBHs) are a group of water-soluble polysaccharides with high molecular weight hydrophilic long-chain molecules, which are widely employed in food industry as thickeners, emulsifiers, gelling agents, and stabilizers. Pasta products are considered to be an important source of nutrition for humans, and PBHs show great potential in improving their quality and nutritional value. The hydration of PBHs to form viscous solutions or sols under specific processing conditions is a prerequisite for improving the stability of food systems. In this review, PBHs are classified in a novel way according to food processing conditions, and their gelation mechanisms are summarized. The application of PBHs in pasta products prepared under different processing methods (baking, steaming/cooking, frying, freezing) are reviewed, and the potential mechanism of PBHs in regulating pasta products quality is revealed from the interaction between PBHs and the main components of pasta products (protein, starch, and water). Finally, the safety of PBHs is critically explored, along with future perspectives. This review provides a scientific foundation for the development and specific application of PBHs in pasta products, and provides theoretical support for improving pasta product quality.


Assuntos
Farinha , Manipulação de Alimentos , Humanos , Farinha/análise , Amido , Culinária , Água
12.
J Food Sci ; 88(7): 2740-2757, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37282778

RESUMO

Oven roasting (OR) could induce hierarchical structural changes in starch, which is fundamental for altering the pasting and hydration properties of cereal flour. OR makes proteins denatured and peptide chains unraveled or rearranged. OR could alter compositions of cereal lipids and minerals. Although OR may degrade phenolics, their release from bound forms is predominant when mild/moderate conditions are exerted. Hence, some OR-modified cereals even exhibit many physiological functions, such as anti-diabetic and anti-inflammatory activity. Furthermore, these minor components interplay with starch/protein via physical entrapment, non-covalent interactions, or cross-linking. The structural changes and interactions modulate functionalities of OR-modified cereal flour, its dough/batter property, and related staple food quality. Compared with hydrothermal or high-pressure thermal treatments, proper OR even induces greater enhancement in technological quality and bioactive compounds release. Given the simple operation and low cost, it is worth utilizing OR for the development of sensory-appealing healthy staple foods.


Assuntos
Grão Comestível , Farinha , Farinha/análise , Grão Comestível/química , Amido/química , Qualidade dos Alimentos
13.
Int J Biol Macromol ; 243: 125076, 2023 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-37244337

RESUMO

The changes of intact endosperm cell wall in cereal food processing and its effect on starch digestibility are important for developing nutritious and healthy next generation foods, but their changes in the process of traditional Chinese cooking products such as noodles making have not been investigated. In this paper, the changes in endosperm cell wall in the process of making dried noodles by adding 60 % wheat farina with varied particle sizes were tracked, and the underlying mechanisms affecting the noodle quality and starch digestibility were revealed. With increasing particle size (150-800 µm) of farina, the contents of starch and protein, swelling index of glutenin, and sedimentation value decreased significantly and the dietary fiber increased sharply; moreover, water absorption, stability and extensibility of dough decline obviously while the resistance to extension and thermal stability were enhanced. In addition, noodles made with flour added larger-particle size farina had a lower hardness, springiness, and stretchability while a higher adhesiveness. Compared to the flour and other samples, the flour with the smaller-particle size farina (150-355 µm) showed better rheological properties of dough and cooking quality of noodles. Furthermore, the integrity of the endosperm cell wall increased with increasing particle size (150-800 µm), which was perfectly preserved during noodle processing and was an effective physical barrier to inhibit starch digestion. The starch digestibility of noodles made from mixed farina with low protein content (∼15 %) did not significantly reduce compared to that of wheat flour noodles with high protein content (∼18 %), probably due to the increased cell wall permeability of noodle processing, or the overwhelming effect of noodle structure or protein content. In conclusion, our findings will contribute to an innovative perspective for in-depth understanding of the impact of endosperm cell wall on the quality and nutrition of noodles at the cellular level, which provided a theoretical basis for the moderate processing of wheat flour and the development of healthier wheat-based food products.


Assuntos
Endosperma , Amido , Endosperma/metabolismo , Amido/química , Triticum/química , Farinha/análise , Culinária , Parede Celular/metabolismo
14.
Cytotherapy ; 25(5): 472-482, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36863932

RESUMO

Long-term or high-dose use of glucocorticoids causes bone loss and low bone formation. We previously demonstrated that dexamethasone (Dex) administration caused the shifted differentiation balance of mesenchymal stromal cells (MSCs) to favor adipogenic lineage over osteoblastic lineage, which is one of the key mechanisms for Dex-induced osteoporosis (DIO). These findings indicate that supplementing functional allogeneic MSCs could be a therapeutic strategy for DIO. Here, we found that transplanting MSCs by intramedullary injection had little effect in promoting new bone formation. Fluorescent-labeled lineage tracing revealed that 1 week after transplantation, green fluorescent protein (GFP)-MSCs were found to migrate to the bone surface (BS) in control mice but not in DIO mice. As expected, GFP-MSCs on the BS were mostly Runx2-positive; however, GFP-MSCs located away from the BS failed to differentiate into osteoblasts. We further discovered that the levels of transforming growth factor beta 1 (TGF-ß1), one of the main chemokines for MSC migration, is significantly decreased in the bone marrow fluid of DIO mice, which is insufficient to direct MSC migration. Mechanistically, Dex inhibits TGF-ß1 expression by down-regulating its promoter activity, which decreases bone matrix-deposited TGF-ß1 as well as active TGF-ß1 released during osteoclast-mediated bone resorption. This study indicates that blocking MSC migration in osteoporotic BM contributes to bone loss and suggests that MSC mobilization to the BS may be a promising target for treating osteoporosis.


Assuntos
Células-Tronco Mesenquimais , Osteoporose , Camundongos , Animais , Glucocorticoides/metabolismo , Glucocorticoides/farmacologia , Osteogênese/fisiologia , Fator de Crescimento Transformador beta1/metabolismo , Diferenciação Celular
15.
Sci Rep ; 13(1): 387, 2023 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-36617577

RESUMO

The purpose of this study was to investigate the association between time restricted feeding (TRF) and different areas of cognitive function in the elderly in Chinese communities. This study consisted of 1353 community-dwelling Chinese older adults aged 60 years and older in Chongming area, Shanghai (563 males; the mean age, 73.38 ± 6.16 years). Mild cognitive impairment (MCI) and six different cognitive domains was assessed by the Chinese-version of Mini Mental State Examination (MMSE). Recording the eating time of each meal through oral inquiry to calculate the time window between the first meal and the last meal of the average day. Participants with an eating time window duration of more than 10 h were then identified, as well as those with eating time restricted to less than 10 h (TRF). Our study found that TRF may be associated with a higher incidence rate of cognitive impairment. TRF only limited the eating time window and did not change the frequency of participants' dietary intake. We used a linear regression model to study the association of TRF with cognitive function. After adjusting for confounding variables, the results showed that TRF was related to MMSE score (P < 0.001), "Orientation to place" (P < 0.001) and "Attention/calculation" (P < 0.001) functions. Among Chinese older community-dwellers, TRF was associated with a higher prevalence of CI and negatively correlated with the "Orientation to place" and "attention/calculation" functions.


Assuntos
Disfunção Cognitiva , Jejum Intermitente , Idoso , Masculino , Humanos , Pessoa de Meia-Idade , População do Leste Asiático , China/epidemiologia , Cognição
16.
Biometals ; 36(3): 587-601, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36342570

RESUMO

Weaning is a crucial period in the pig's life cycle, which is frequently followed by gastrointestinal (GI) infections, diarrhea and even death. This study focused on the impact of bovine lactoferrin (bLF) supplementation on the intestinal health of weaning piglets. Weaning piglets (Duroc × Landrace × Yorkshire, 23 days) were randomly allocated into four groups, which included negative control group (CON): basic diet; positive control group (ANT): basic diet + 20 mg/kg flavomycin + 100 mg/kg aureomycin; treatment group bLF-A: basic diet + 1 g/kg bLF; treatment group bLF-B: basic diet + 3 g/kg bLF. The result showed that dietary supplementation of bLF can improve growth performance and reduce diarrhea, which exhibits dose-dependency (P < 0.05). Compared with CON group, supplementation with bLF significantly improved immunity, and increased villus height and ratio of villus height/crypt depth at the small intestinal mucosa (P < 0.05). The mRNA expression of claudin-1, occludin and ZO-1 was greatly increased in the ileum of bLF group on days 7 and 14 (P < 0.05). Furthermore, the supplementation of bLF increased the abundance of Lactobacillus and Bifidobacterium and decreased the abundance of Escherichia coli in the cecum on day 7 (P < 0.05). The dietary supplementation of bLF enhanced the growth performance, reduced diarrhea rate in weaning piglets by improving intestinal immunity, morphology and barrier function, balancing intestinal microbiota. And bLF can be a promising feed additive in relieving stress situation of weaning piglets.


Assuntos
Suplementos Nutricionais , Lactoferrina , Estresse Psicológico , Suínos , Desmame , Animais , Diarreia/prevenção & controle , Diarreia/metabolismo , Dieta/veterinária , Escherichia coli/metabolismo , Imunidade , Mucosa Intestinal/metabolismo , Lactoferrina/farmacologia , Lactoferrina/metabolismo , Estresse Psicológico/prevenção & controle
17.
Foods ; 12(23)2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-38231610

RESUMO

A Sorghum flour (SF) is a leading and prominent food source for humans in African countries. Recently extensive studies have been conducted on Sorghum bread (SB) or sorghum composite bread (SCB), covering various aspects. However, there are many technical challenges in the formation of SF and sorghum composite flour (SCF) that impact the quality of the bread and fail to meet the consumer's desires and expectations. This review primarily focuses on the characteristics of SF, SCF, SB, and SCB, with discussions encompassing the rheological and morphological properties of the dough, improvement strategies, and bread quality. Moreover, a comprehensive analysis has been conducted to investigate the behavior of SF and SCF along with a discussion of the challenges affecting bread quality and the strategies applied for improvement. The significant demand for nutrients-rich and gluten-free bread indicates that sorghum will become one of the most vital crops worldwide. However, further comprehensive research is highly demanded and necessary for an in-depth understanding of the key features of SF and the resulting bread quality. Such understanding is vital to optimize the utilization of sorghum grain in large-scale bread production.

18.
Foods ; 11(17)2022 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-36076770

RESUMO

Lactic acid bacteria have been considered to be a very important species during sourdough fermentation. In order to explore the effects of bifidobacteria fermentation on thermal, physico-chemical and structural properties of wheat starch during dough fermentation, starch granules were separated from the fermented dough at different fermentation times, including 0 h, 2 h, 6 h, 9 h and 12 h. The results showed that the morphology of starch granules was destroyed gradually as the fermentation time increased, which appeared as erosion and rupture. With the increase in fermentation time, the solubility showed a significant increase, which changed from 8.51% (0 h) to 9.80% (12 h), and the swelling power was also increased from 9.31% (0 h) to 10.54% (12 h). As for the gelatinization property, the enthalpy was increased from 6.77 J/g (0 h) to 7.56 J/g (12 h), indicating a more stable thermal property of fermented starch, especially for the longer fermentation. The setback value was decreased with short fermentation time, indicating that the starch with a longer fermentation time was difficult to retrograde. The hardness of the gel texture was decreased significantly from 50.11 g to 38.66 g after fermentation for 12 h. The results show that bifidobacteria fermentation is an effective biological modification method of wheat starch for further applications.

19.
AMB Express ; 12(1): 100, 2022 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-35907065

RESUMO

The Gram-negative rod-shaped bacterium Serratia marcescens is an opportunistic pathogen of many organisms, including insects. We report the identification and optimal in vitro chitinase production conditions of a novel chitinolytic S. marcescens strain TC-1 isolated from a naturally infected white grub (Anomala corpulenta) collected from a peanut field at Nanyang city, Henan province, China. Strain identification was conducted by morphological, physiological, biochemical and molecular analyses. The amplified 16S rRNA gene of TC-1 showed a similarity greater than 99% with multiple strains of S. marcescens. Based on Neighbor-joining phylogenetic tree analysis of bacterial 16S rRNA gene sequences, TC-1 formed a clade with S. marcescens, clearly separated from other Serratia spp. The strain TC-1 showed larvicidal activities against five insect species (A. corpulenta, Plutella xylostella, Spodoptera exigua, Helicoverpa armigera, Bombyx mori) and the nematode Caenorhabditis elegans, but not against S. litura. The operating parameters of chitinase production by TC-1 were optimized by response surface methodology using a three-factor, three-level Box-Behnken experimental design. The effects of three independent variables i.e. colloidal chitin concentration (7-13 g l-1), incubation time (24-72 h) and incubation temperature (24-32 °C) on chitinase production by TC-1 were investigated. A regression model was proposed to correlate the independent variables for an optimal chitinase activity predicted as 20.946 U ml-1, using a combination of colloidal chitin concentration, incubation time and incubation temperature of 9.06 g l-1, 63.83 h and 28.12 °C, respectively. The latter agreed well with a mean chitinase activity of 20.761 ± 0.102 U ml-1 measured in the culture supernatants of TC-1 grown under similar conditions with a colloidal chitin concentration, incubation time and incubation temperature of 9 g l-1, 64 h and 28 °C, respectively. Our study revealed the S. marcescens strain TC-1 with potential as a biocontrol agent of insect pests and nematodes and demonstrated the proposed regression model's potential to guide chitinase production by this strain.

20.
Front Microbiol ; 13: 865774, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35722282

RESUMO

Staphylococcus aureus (S. aureus) is one of the most common pathogenic bacteria responsible for causing a life-threatening peritonitis disease. NZX, as a variant of fungal defensin plectasin, displayed potent antibacterial activity against S. aureus. In this study, the antibacterial and resistance characteristics, pharmacokinetics, and pharmacodynamics of NZX against the S. aureus E48 and S. aureus E48-induced mouse peritonitis model were studied, respectively. NZX exhibited a more rapid killing activity to S. aureus (minimal inhibitory concentration, 1 µg/ml) compared with linezolid, ampicillin and daptomycin, and serial passaging of S. aureus E48 for 30 days at 1/2 × MIC, NZX had a lower risk of resistance compared with ampicillin and daptomycin. Also, it displayed a high biocompatibility and tolerance to physiological salt, serum environment, and phagolysosome proteinase environment, except for acid environment in phagolysosome. The murine serum protein-binding rate of NZX was 89.25% measured by ultrafiltration method. Based on the free NZX concentration in serum after tail vein administration, the main pharmacokinetic parameters for T1/2, Cmax, Vd, MRT, and AUC ranged from 0.32 to 0.45 h, 2.85 to 20.55 µg/ml, 1469.10 to 2073.90 ml/kg, 0.32 to 0.56 h, and 1.11 to 8.89 µg.h/ml, respectively. Additionally, the in vivo pharmacodynamics against S. aureus demonstrated that NZX administrated two times by tail vein at 20 mg/kg could rescue all infected mice in the lethal mouse peritonitis model. And NZX treatment (20 mg/kg) significantly reduced CFU counts in the liver, lung, and spleen, especially for intracellular bacteria in the peritoneal fluid, which were similar or superior to those of daptomycin. In vivo efficacies of NZX against total bacteria and intracellular bacteria were significantly correlated with three PK/PD indices of ƒAUC/MIC, ƒCmax/MIC, and ƒT% > MIC analyzed by a sigmoid maximum-effect model. These results showed that NZX may be a potential candidate for treating peritonitis disease caused by intracellular S. aureus.

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