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1.
J Dairy Sci ; 105(10): 7891-7903, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36055836

RESUMO

The amount of intact casein provided by dairy ingredients is a critical parameter in dairy-based imitation mozzarella cheese (IMC) formulation because it has a significant effect on unmelted textural parameters such as hardness. From a functionality perspective, rennet casein (RCN) is the preferred ingredient. Milk protein concentrate (MPC) and micellar casein concentrate (MCC) cannot provide the required functionality due to the higher steric stability of casein micelle. However, the use of transglutaminase (TGase) has the potential to modify the surface properties of MPC and MCC and may improve their functionality in IMC. The objective of this study was to determine the effect of TGase-treated MPC and MCC powders on the unmelted textural properties of IMC and compare them with IMC made using commercially available RCN. Additionally, we studied the degree of crosslinking by TGase in MPC and MCC retentates using capillary gel electrophoresis. Three lots of MCC and MPC retentate were produced from pasteurized skim milk via microfiltration and ultrafiltration, respectively, and randomly assigned to 1 of 3 treatments: no TGase (control); low TGase: 0.3 units/g of protein; and high TGase: 3.0 units/g of protein, followed by inactivation of enzyme (72°C for 10 min), and spray drying. Each MCC, MPC, and RCN was then used to formulate IMC that was standardized to 21% fat, 1% salt, 48% moisture, and 20% protein. The IMC were manufactured by blending, mixing, and heating ingredients (4.0 kg) in a twin-screw cooker. The capillary gel electrophoresis analysis showed extensive inter- and intramolecular crosslinking. The IMC formulation using the highest TGase level in MCC or MPC did not form an emulsion because of extensive crosslinking. In MPC with a high level of TGase, whey protein and casein crosslinking were observed. In contrast, crosslinking and hydrolysis of proteins were observed in MCC. The IMC made from MCC powder had significantly higher texture profile analysis hardness compared with the corresponding MPC powder. Further, many-to-one (multiple) comparisons using the Dunnett test showed no significant differences between IMC made using RCN and treatment powders in hardness. Our results demonstrated that TGase treatment causes crosslinking hydrolysis of MCC and MPC at higher TGase levels, and MPC and MCC have the potential to be used as ingredients in IMC applications.


Assuntos
Caseínas , Queijo , Animais , Caseínas/análise , Queijo/análise , Emulsões , Manipulação de Alimentos/métodos , Comportamento Imitativo , Micelas , Proteínas do Leite/análise , Pós , Transglutaminases , Proteínas do Soro do Leite/análise
2.
J Dairy Sci ; 105(10): 7904-7916, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36055846

RESUMO

Melt and stretch properties in dairy-based imitation mozzarella cheese (IMC) are affected by the amount of intact casein provided by dairy ingredients in the formulation. Rennet casein (RCN) is the preferred ingredient to provide intact casein in a formulation. Ingredients produced using membrane technology, such as milk protein concentrate (MPC) and micellar casein concentrate (MCC), are unable to provide the required functionality. However, the use of transglutaminase (TGase) has potential to modify the physical properties of MPC or MCC and may improve their functionality in IMC. The objective of this study was to determine the effect of TGase-treated MPC and MCC retentates on melt and stretch properties when they are used in IMC and to compare them with IMC made using RCN. The MCC and MPC retentates were produced using 3 different lots of pasteurized skim milk and treated with 3 levels of TGase enzyme: no TGase (control), low TGase: 0.3 units/g of protein, and high TGase: 3.0 units/g of protein. Each of the MCC and MPC treatments was heated to 72°C for 10 min to inactivate TGase and then spray dried. Each MCC, MPC, and RCN powder was then used in an IMC formulation that was standardized to 48% moisture, 21% fat, 20% protein, and 1% salt. The IMC were manufactured in a twin-screw cooker by blending, mixing, and heating various ingredients (4.0 kg). Due to extensive crosslinking, the IMC formulation with the highest TGase level (MCC or MPC) did not form an emulsion. The IMC made from MCC treatments had significantly higher stretchability on pizza compared with their respective MPC treatments. The IMC made from TGase-treated MCC and MPC had significantly lower melt area and significantly higher transition temperature (TT) and stretchability compared with their respective controls. Comparison of IMC made using TGase-treated MCC and MPC to the RCN IMC indicated no difference in TT or texture profile analysis-stretchability; however, the Schreiber melt test area was significantly lower. Our results demonstrated that TGase treatment modifies the melt and stretch characteristics of MCC and MPC in IMC applications, and TGase-treated MPC and MCC can be used to replace RCN in IMC formulations.


Assuntos
Queijo , Animais , Caseínas , Queijo/análise , Emulsões , Manipulação de Alimentos/métodos , Comportamento Imitativo , Micelas , Proteínas do Leite/metabolismo , Pós , Transglutaminases
3.
BMC Gastroenterol ; 22(1): 375, 2022 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-35933327

RESUMO

BACKGROUND: Celiac disease (CD) is a genetically determined autoimmune disease triggered by gluten consumption. Patients with these conditions have intraepithelial lymphocytosis, crypt hyperplasia, and severe intestinal atrophy. Gluten elimination is the only way to reduce this chronic inflammation. The diagnosis of CD is usually made by analyzing anti-tTG, anti-DGP, or EMA serological tests, and it is confirmed by biopsy of the duodenum. In people with CD, xerostomia or dry mouth is a common complication. This condition causes the salivary glands to malfunction and, in turn, may result in oral plaque and periodontal disease. By comparing salivary and serum levels of tissue transglutaminase IgA (tTG-IgA), this study aims to suggest a non-invasive method for diagnosis of CD. Furthermore, the present study evaluates the severity of xerostomia symptoms in people with CD. METHODS: In this case-control study, participants were patients referred to the internal ward of Sayyad Shirazi hospital. The control group was selected from healthy people who attended Gorgan Dental College. In this study, an analysis of serum was performed following consent from patients. This was followed by a salivary test, and the results of both tests were compared. The Xerostomia Inventory questionnaire was also used to determine the severity of xerostomia. As part of this study, examination of factors such as total protein concentration of saliva, albumin concentration, amylase level, pH, sodium, calcium, potassium, phosphorus, and interleukin (6, 18, and 21) were conducted. RESULTS: A total of 78 people were studied (aged 15 to 68), 26 were male (33.3%) and 52 were female (66.7%). In comparisons of the serum and saliva of people with and without CD, the level of amylase was higher in the latter group. The average levels of IL-6، IL-18 ،IL-21, and salivary and serum tTG were higher in people with CD. Additionally, CD patients were more likely to develop xerostomia. CONCLUSION: Study findings showed that CD can reduce certain salivary enzymes and elements, as well as increase inflammatory cytokines, salivary, and serum tTG. The management of dry mouth should also be recommended for celiac disease patients in order to prevent its complications.


Assuntos
Doença Celíaca , Xerostomia , Amilases , Autoanticorpos , Estudos de Casos e Controles , Doença Celíaca/complicações , Doença Celíaca/diagnóstico , Feminino , Glutens , Humanos , Imunoglobulina A , Masculino , Proteína 2 Glutamina gama-Glutamiltransferase , Transglutaminases , Xerostomia/etiologia
4.
Sci Rep ; 12(1): 13578, 2022 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-35945258

RESUMO

cDNA display is an in vitro display technology based on a covalent linkage between a protein and its corresponding mRNA/cDNA, widely used for the selection of proteins and peptides from large libraries (1012) in a high throughput manner, based on their binding affinity. Here, we developed a platform using cDNA display and next-generation sequencing (NGS) for rapid and comprehensive substrate profiling of transglutaminase 2 (TG2), an enzyme crosslinking glutamine and lysine residues in proteins. After screening and selection of the control peptide library randomized at the reactive glutamine, a combinatorial library of displayed peptides randomized at positions - 1, + 1, + 2, and + 3 from the reactive glutamine was screened followed by NGS and bioinformatic analysis, which indicated a strong preference of TG2 towards peptides with glutamine at position - 1 (Gln-Gln motif), and isoleucine or valine at position + 3. The highly enriched peptides indeed contained the indicated sequence and showed a higher reactivity as TG2 substrates than the peptide previously selected by phage display, thus representing the novel candidate peptide probes for TG2 research. Furthermore, the obtained information on substrate profiling can be used to identify potential TG2 protein targets. This platform will be further used for the substrate profiling of other TG isozymes, as well as for the selection and evolution of larger biomolecules.


Assuntos
Proteínas de Ligação ao GTP , Transglutaminases , Biologia Computacional , DNA Complementar , Proteínas de Ligação ao GTP/metabolismo , Glutamina/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Biblioteca de Peptídeos , Peptídeos/química , Proteína 2 Glutamina gama-Glutamiltransferase , Especificidade por Substrato , Transglutaminases/metabolismo
5.
Front Immunol ; 13: 847092, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35967379

RESUMO

Certain CD8 T cell responses are particularly effective at controlling infection, as exemplified by elite control of HIV in individuals harboring HLA-B57. To understand the structural features that contribute to CD8 T cell elite control, we focused on a strongly protective CD8 T cell response directed against a parasite-derived peptide (HF10) presented by an atypical MHC-I molecule, H-2Ld. This response exhibits a focused TCR repertoire dominated by Vß2, and a representative TCR (TG6) in complex with Ld-HF10 reveals an unusual structure in which both MHC and TCR contribute extensively to peptide specificity, along with a parallel footprint of TCR on its pMHC ligand. The parallel footprint is a common feature of Vß2-containing TCRs and correlates with an unusual Vα-Vß interface, CDR loop conformations, and Vß2-specific germline contacts with peptides. Vß2 and Ld may represent "specialist" components for antigen recognition that allows for particularly strong and focused T cell responses.


Assuntos
Linfócitos T CD8-Positivos , Peptídeos , Receptores de Antígenos de Linfócitos T alfa-beta , Receptores de Antígenos de Linfócitos T , Linfócitos T CD8-Positivos/imunologia , Células Germinativas/imunologia , Antígeno de Histocompatibilidade H-2D/imunologia , Conformação Molecular , Peptídeos/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Transglutaminases/imunologia
6.
Int J Mol Sci ; 23(16)2022 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-36012345

RESUMO

The main aim of the research was to develop a new biocompatible and injectable composite with the potential for application as a bone-to-implant bonding material or as a bone substitute. A composite based on hydroxyapatite, gelatin, and two various types of commercially available transglutaminase (TgBDF/TgSNF), as a cross-linking agent, was proposed. To evaluate the impacts of composite content and processing parameters on various properties of the material, the following research was performed: the morphology was examined by SEM microscopy, the chemical structure by FTIR spectroscopy, the degradation behavior was examined in simulated body fluid, the injectability test was performed using an automatic syringe pump, the mechanical properties using a nanoindentation technique, the surface wettability was examined by an optical tensiometer, and the cell viability was assayed by MTT and LDH. In all cases, a composite paste was successfully obtained. Injectability varied between 8 and 15 min. The type of transglutaminase did not significantly affect the surface topography or chemical composition. All samples demonstrated proper nanomechanical properties with Young's modulus and the hardness close to the values of natural bone. BDF demonstrated better hydrophilic properties and structural stability over 7 days in comparison with SNF. In all cases, the transglutaminase did not lead to cell necrosis, but cellular proliferation was significantly inhibited, especially for the BDF agent.


Assuntos
Durapatita , Gelatina , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Cerâmica/farmacologia , Durapatita/química , Gelatina/química , Engenharia Tecidual/métodos , Transglutaminases
7.
Int J Mol Sci ; 23(16)2022 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-36012648

RESUMO

Salecan (Sal) is a novel marine microbial polysaccharide. In the present research, Sal and soy protein isolate (SPI) were adopted to fabricate Sal-SPI composite hydrogel based on a stepwise process (thermal treatment and transglutaminase induction). The effect of Sal concentration on morphology, texture properties, and the microstructure of the hydrogel was evaluated. As Sal concentration varied from 0.4 to 0.6 wt%, hydrogel elasticity increased from 0.49 to 0.85 mm. Furthermore, the internal network structure of Sal-SPI composite hydrogel also became denser and more uniform as Sal concentration increased. Rheological studies showed that Sal-SPI elastic hydrogel formed under the gelation process. Additionally, FTIR and XRD results demonstrated that hydrogen bonds formed between Sal and SPI molecules, inferring the formation of the interpenetrating network structure. This research supplied a green and simple method to fabricate Sal-SPI double network hydrogels.


Assuntos
Hidrogéis , beta-Glucanas , Hidrogéis/química , Proteínas de Soja/metabolismo , Transglutaminases/metabolismo , beta-Glucanas/química
8.
Food Funct ; 13(17): 8941-8950, 2022 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-35929785

RESUMO

A lifelong gluten-free diet (GFD) is currently the only available therapy for coeliac disease (CD). However, GFD compliance is difficult and alternative strategies are envisaged in the near future. We previously found that wheat gliadin following transamidation by microbial transglutaminase (mTG) does not induce IFN-γ secretion by intestinal T cells from CD patients. Fully transamidated gliadin with lysine ethyl ester can be recovered in a soluble protein fraction (spf) generated by the enzymatic treatment of wheat flour. Herein, we analysed the performance of transamidation by mTG on a pilot-scale (1L) by evaluating the reaction kinetics and its biological effect on the intestinal immune response in HLA/DQ8 transgenic mice, a model of gluten sensitivity. At 1 h, all gliadin fractions showed a faster electrophoretic mobility by acid-polyacrylamide gel electrophoresis (A-PAGE) following transamidation in comparison with their native counterparts. In parallel, the yield of residual native gliadin dropped (30% at 180 min), confirming our previous findings on a lab scale. Mucosal sensitisation of mice with gliadin via the intranasal route induced a Th1 phenotype in mesenteric lymph nodes (MLNs). Importantly, IFN-γ secretion was significantly reduced when gliadin-specific MLN cells were challenged in vitro with spf (P < 0.001). Multiplex analysis revealed that the adaptive immune response evoked by spf involved a distinct cell population characterised by secretion of IL-2, IL-3 and IL-5. Notably, spf stimulated in vitro a reduced or null secretion of all of the examined pro-inflammatory markers mainly associated to innate immunity. In conclusion, our data revealed the ability of transamidated gliadin to modulate both innate and adaptive mechanisms involved in the inflammatory response induced by wheat gliadin in the small intestine of DQ8 mice.


Assuntos
Doença Celíaca , Gliadina , Animais , Doença Celíaca/metabolismo , Farinha , Gliadina/metabolismo , Glutens/metabolismo , Antígenos HLA-DQ/imunologia , Intestino Delgado/metabolismo , Camundongos , Camundongos Transgênicos , Transglutaminases/metabolismo , Triticum/metabolismo
9.
Mar Biotechnol (NY) ; 24(4): 801-819, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35915285

RESUMO

Marine animal by-products of the food industry are a great source of valuable biomolecules. Skins and bones are rich in collagen, a protein with various applications in food, cosmetic, healthcare, and medical industries in its native form or partially hydrolyzed (gelatin). Salmon gelatin is a candidate of interest due to its high biomass production available through salmon consumption, its biodegradability, and its high biocompatibility. However, its low mechanical and thermal properties can be an obstacle for various applications requiring cohesive material. Thus, gelatin modification by cross-linking is necessary. Enzymatic cross-linking by microbial transglutaminase (MTG) is preferred to chemical cross-linking to avoid the formation of potentially cytotoxic residues. In this work, the potential of salmon skin gelatin was investigated, in a comparative study with porcine gelatin, and an enzymatic versus chemical cross-linking analysis. For this purpose, the two cross-linking methods were applied to produce three-dimensional, porous, and mechanically reinforced hydrogels and sponges with different MTG ratios (2%, 5%, and 10% w/w gelatin). Their biochemical, rheological, and structural properties were characterized, as well as the stability of the material, including the degree of syneresis and the water-binding capacity. The results showed that gelatin enzymatically cross-linked produced material with high cross-linking densities over 70% of free amines. The MTG addition seemed to play a crucial role, as shown by the increase in mechanical and thermal resistances with the production of a cohesive material stable above 40 °C for at least 7 days and comparable to porcine and chemically cross-linked gelatins. Two prototypes were obtained with similar thermal resistances but different microstructures and viscoelastic properties, due to different formation dynamics of the covalent network. Considering these results, the enzymatically cross-linked salmon gelatin is a relevant candidate as a biopolymer for the production of matrix for a wide range of biotechnological applications such as food packaging, cosmetic patch, wound healing dressing, or tissue substitute.


Assuntos
Materiais Biomiméticos , Salmo salar , Animais , Reagentes de Ligações Cruzadas/química , Embalagem de Alimentos , Gelatina/química , Salmo salar/metabolismo , Suínos , Transglutaminases
10.
Am J Gastroenterol ; 117(9): 1428-1436, 2022 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-35973169

RESUMO

INTRODUCTION: We evaluated whether persistent-positive celiac serology is associated with the risk of hypothyroidism. METHODS: We extracted a cohort of subjects aged 1-80 years with a positive IgA anti-tissue transglutaminase between January 1, 2008, and December 31, 2012, and a repeat anti-tissue transglutaminase test within 6-36 months from a large population-based electronic medical record database. Based on serology tests, we categorized the pediatric (age <21 years) and adult cohorts into normalized or persistent-positive serology groups. All subjects were followed up for incident diagnosis of hypothyroidism from the last serology date up to December 31, 2017. Hazard ratio (HR) along 95% confidence intervals (CIs) were prepared to evaluate the association of celiac serology group with a diagnosis of hypothyroidism, crude, and adjusted for age, sex, and diagnosis of type 1 diabetes mellitus. RESULTS: Among the pediatric cohort (n = 2,687), during a median follow-up of 64 months (interquartile range 48-80), 2.3% (16/681) of the persistent-positive serology group and 1.0% (20/2,006) of the normalized serology group developed hypothyroidism (HR 2.07 [95% CI 1.07-4.44], adjHR 1.77 [95% CI 0.91-3.46]). The rate among the pediatric cohort with an established diagnosis of celiac disease was 3.4% (10/486) vs 1.0% (5/481), HR 2.83 (0.96-8.32). In the adult cohort (n = 1,286), 4.5% (20/442) of the persistent-positive group and 3.9% (33/811) of the normalized serology group developed hypothyroidism (HR 1.13 [95% CI 0.65-1.97]). DISCUSSION: In this retrospective, age-stratified analysis, we report that persistent-positive serology may be associated with the risk of hypothyroidism among the pediatric population. Prospective cohorts are needed to validate our findings.


Assuntos
Doença Celíaca , Hipotireoidismo , Adulto , Doença Celíaca/complicações , Doença Celíaca/diagnóstico , Doença Celíaca/epidemiologia , Criança , Estudos de Coortes , Proteínas de Ligação ao GTP , Humanos , Hipotireoidismo/epidemiologia , Estudos Prospectivos , Estudos Retrospectivos , Transglutaminases
11.
Food Funct ; 13(17): 9049-9059, 2022 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-35943369

RESUMO

The crosslinking and drying method of microcapsules prepared by complex coacervation has been investigated in order to achieve a better control of the oxidative stability of the final powder product. Methyl oleate was microencapsulated with gelatin and gum arabic as wall materials. For improving the oxidative stability of microcapsules, the crosslinking and drying method was optimized in order to obtain a product with a stable and dense wall layer structure. The wall layer crosslinked by transglutaminase was found to be more thermostable than other food-grade crosslinking agents. Combined uses of different crosslinking agents had been carried out for microcapsules obtained by freeze drying, and the product crosslinked in turn by transglutaminase and tannic acid exhibited the relatively best oxidative stability measured by oxidation induction time. However, a new method of organic solvent replacement drying was found to be more suitable for drying microcapsules, since this method could achieve better oxidative stability than freeze or spray drying even by using transglutaminase or tannic acid alone as the crosslinking agent. The SEM graphs showed that this new drying method could avoid ice crystal formation and reduce the external force during the drying process, thus effectively reducing the occurrence of micro-holes in the wall layer and inhibiting the adhesion between the microcapsules. From the analysis of the secondary structure measurement, this new drying method could convert irregular structures into α-helical structures, hence enhancing the compactness of the wall layer structure. The organic solvent replacement drying method is an economical and environmental method with promising application prospects.


Assuntos
Taninos , Transglutaminases , Cápsulas/química , Composição de Medicamentos/métodos , Liofilização , Lipídeos , Estresse Oxidativo , Solventes
12.
Int J Mol Sci ; 23(14)2022 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-35886862

RESUMO

Type 2 transglutaminase (TG2) is the main autoantigen in coeliac disease (CD), a widespread inflammatory enteropathy caused by the ingestion of gluten-containing cereals in genetically predisposed individuals. As a consequence, serum antibodies to TG2 represent a very useful marker in CD diagnosis. However, TG2 is also an important player in CD pathogenesis, for its ability to deamidate some Gln residues of gluten peptides, which become more immunogenic in CD intestinal mucosa. Given the importance of TG2 enzymatic activities in CD, several studies have sought to discover specific and potent inhibitors that could be employed in new therapeutical approaches for CD, as alternatives to a lifelong gluten-free diet. In this review, we summarise all the aspects regarding TG2 involvement in CD, including its enzymatic reactions in pathogenesis, the role of anti-TG2 antibodies in disease management, and the exploration of recent strategies to reduce deamidation or to use transamidation to detoxify gluten.


Assuntos
Doença Celíaca , Proteína 2 Glutamina gama-Glutamiltransferase , Autoanticorpos , Doença Celíaca/diagnóstico , Doença Celíaca/etiologia , Doença Celíaca/terapia , Proteínas de Ligação ao GTP/metabolismo , Glutens/química , Humanos , Proteína 2 Glutamina gama-Glutamiltransferase/metabolismo , Transglutaminases/metabolismo
13.
Mymensingh Med J ; 31(3): 704-710, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35780354

RESUMO

This cross sectional, descriptive study was conducted at Paediatrics department of BSMMU from July 2016 to June 2018 to find out histopathological pattern of Coeliac disease according to Modified Marsh criteria and to correlate it with tissue transglutaminase IgA level. A total of 62 children (age <18 years) attending the Paediatrics department of BSMMU with clinical suspicion of celiac disease were enrolled for the study. Mean age of studied children was 7.87±4.67 years. Ratio of the male and female was 2.27:1. Maximum (66.1%) children came from middle income class family. Out of 62 children, 35.5% (22) were positive for IgA anti-tTG of who female were 11.3% and male 24.2%. Mean duration of symptoms was 44.07±21.77 months in serology positive patients and 34.49±30.52 months in serology negative patients. The age group, 10-14 year showed the highest (50.0%) prevalence of positive anti-tTG. In the tTG positive group mean Hb was 9.6±1.14gm/dl and which is lower than that in tTG negative group (11.7±1.47gm/dl). Among 22 sero-positive patients, histological changes compatible with CD were found in 19 (86.3%) cases and normal in 3 cases. Histological changes were of 3a category of Marsh was found in 12(63.2%) cases, 3b in 4(21.1%) cases and 3c in 3(15.8%) cases. Strong correlation was observed between the serological level of tTGA and histological types of CD by Modified Marsh criteria. In conclusion, screening for celiac disease may be included in diagnostic tests to investigate clinically suspected children and serum tTGA level can be used to predict histopathological severity of coeliac disease.


Assuntos
Doença Celíaca , Adolescente , Autoanticorpos , Biópsia , Doença Celíaca/diagnóstico , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Imunoglobulina A , Masculino , Proteína 2 Glutamina gama-Glutamiltransferase , Transglutaminases
14.
Sheng Wu Gong Cheng Xue Bao ; 38(7): 2499-2512, 2022 Jul 25.
Artigo em Chinês | MEDLINE | ID: mdl-35871620

RESUMO

Protein cross-linking plays important roles in food, chemical, medicine and other fields. Enzyme-catalyzed protein cross-linking is an efficient and economically viable alternative to physical and chemical cross-linking. However, detailed analysis of enzyme-catalyzed protein cross-linking at molecular level is still lacking. This review summarized the mechanisms of enzyme-catalyzed protein cross-linking, its effects on protein structure, and its applications in food, chemical and pharmaceutical fields.


Assuntos
Proteínas , Transglutaminases , Catálise , Reagentes de Ligações Cruzadas/química , Reagentes de Ligações Cruzadas/metabolismo , Proteínas/química , Transglutaminases/metabolismo
15.
J Dairy Sci ; 105(9): 7253-7265, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35863927

RESUMO

This study investigated the effect of ultrasound and enzymatic cross-linking on the freeze-thaw (FT) stability and release properties of whey protein isolate hydrogels. We evaluated the FT stability by the changes in the microstructure, riboflavin retention, syneresis, water holding capacity (WHC), and texture of gels subjected to 3 FT cycles. High-intensity ultrasound (HUS) and transglutaminase (TGase)-mediated cross-linking improved the FT stability of whey protein isolate hydrogels loaded with riboflavin (WPISAR), as demonstrated by a more uniform and denser porous structure, significantly higher riboflavin retention, WHC, and textural properties, and lower syneresis after 3 FT cycles than those of untreated hydrogels. Furthermore, HUS- and TGase-mediated cross-linking decreased protein erosion and swelling ratio of WPISAR in simulated gastrointestinal fluids (SGIF) and reduced the riboflavin release rate in SGIF both with and without the addition of digestive enzymes. After 3 FT cycles, faster riboflavin release occurred due to a more porous structure induced by ice crystal formation compared with their unfrozen counterparts as detected by confocal laser scanning microscopy. High-intensity ultrasound- and TGase-mediated cross-linking alleviated the FT-induced faster riboflavin release rate in SGIF. High-intensity ultrasound- and TGase-treated gel samples showed that both diffusion and network erosion were responsible for riboflavin release regardless of FT. These results suggest that HUS- and TGase-mediated cross-linking improved the FT stability of WPISAR with a high riboflavin retention, and might be a good candidate as a controlled-release vehicle for riboflavin delivery to overcome undesired FT processing.


Assuntos
Hidrogéis , Transglutaminases , Animais , Congelamento , Riboflavina , Transglutaminases/metabolismo , Proteínas do Soro do Leite/química
16.
Matrix Biol ; 111: 226-244, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35779741

RESUMO

Lack of type VII collagen (C7) disrupts cellular proteostasis yet the mechanism remains undescribed. By studying the relationship between C7 and the extracellular matrix (ECM)-associated proteins thrombospondin-1 (TSP1), type XII collagen (C12) and tissue transglutaminase (TGM2) in primary human dermal fibroblasts from multiple donors with or without the genetic disease recessive dystrophic epidermolysis bullosa (RDEB) (n=31), we demonstrate that secretion of each of these proteins is increased in the presence of C7. In dermal fibroblasts isolated from patients with RDEB, where C7 is absent or defective, association with the COPII outer coat protein SEC31 and ultimately secretion of each of these ECM-associated proteins is reduced and intracellular levels are increased. In RDEB fibroblasts, overall collagen secretion (as determined by the levels of hydroxyproline in the media) is unchanged while traffic from the ER to Golgi of TSP1, C12 and TGM2 occurs in a type I collagen (C1) dependent manner. In normal fibroblasts association of TSP1, C12 and TGM2 with the ER exit site transmembrane protein Transport ANd Golgi Organization-1 (TANGO1) as determined by proximity ligation assays, requires C7. In the absence of wild-type C7, or when ECM-associated proteins are overexpressed, C1 proximity and intracellular levels increase resulting in elevated cellular stress responses and elevated TGFß signaling. Collectively, these data demonstrate a role for C7 in loading COPII vesicle cargo and provides a mechanism for disrupted proteostasis, elevated cellular stress and increased TGFß signaling in patients with RDEB. Furthermore, our data point to a threshold of cargo loading that can be exceeded with increased protein levels leading to pathological outcomes in otherwise normal cells.


Assuntos
Epidermólise Bolhosa Distrófica , Proteostase , Colágeno Tipo VII/genética , Colágeno Tipo VII/metabolismo , Epidermólise Bolhosa Distrófica/genética , Fibroblastos/metabolismo , Humanos , Fator de Crescimento Transformador beta/metabolismo , Transglutaminases/genética , Transglutaminases/metabolismo
17.
Cells ; 11(11)2022 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-35681474

RESUMO

Tissue transglutaminase (TG2) is a member of the transglutaminase family that catalyzes Ca2+-dependent protein crosslinks and hydrolyzes guanosine 5'-triphosphate (GTP). The conformation and functions of TG2 are regulated by Ca2+ and GTP levels; the TG2 enzymatically active open conformation is modulated by high Ca2+ concentrations, while high intracellular GTP promotes the closed conformation, with inhibition of the TG-ase activity. TG2's unique characteristics and its ubiquitous distribution in the intracellular compartment, coupled with its secretion in the extracellular matrix, contribute to modulate the functions of the protein. Its aberrant expression has been observed in several cancer types where it was linked to metastatic progression, resistance to chemotherapy, stemness, and worse clinical outcomes. The N-terminal domain of TG2 binds to the 42 kDa gelatin-binding domain of fibronectin with high affinity, facilitating the formation of a complex with ß-integrins, essential for cellular adhesion to the matrix. This mechanism allows TG2 to interact with key matrix proteins and to regulate epithelial to mesenchymal transition and stemness. Here, we highlight the current knowledge on TG2 involvement in cancer, focusing on its roles translating extracellular cues into activation of oncogenic programs. Improved understanding of these mechanisms could lead to new therapeutic strategies targeting this multi-functional protein.


Assuntos
Neoplasias , Proteína 2 Glutamina gama-Glutamiltransferase , Transição Epitelial-Mesenquimal , Proteínas de Ligação ao GTP/metabolismo , Guanosina Trifosfato , Humanos , Neoplasias/patologia , Transglutaminases/metabolismo
18.
Biomed Res Int ; 2022: 2756242, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35669726

RESUMO

Celiac disease (CeD) is a chronic, immune-mediated enteropathy that is precipitated by dietary gluten in genetically predisposed individuals expressing HLA-DQ2 and/or HLA-DQ8. In the current clinical practice, there are many serologic studies to aid in the diagnosis of CeD which include autoantibodies like IgA antitissue transglutaminase, antiendomysium, and antideamidated forms of gliadin peptide antibodies. Small intestinal biopsy has long been considered an essential step for the diagnosis of CeD. However, in the recent era, researchers have explored the possibility of CeD screening and diagnosis without endoscopy or biopsy. The newer emerging biomarkers of CeD appear promising in diagnostic evaluation and subsequent monitoring of disease. In this review of literature, we have explored the emerging biomarker-based diagnostic evaluation and monitoring of CeD.


Assuntos
Doença Celíaca , Autoanticorpos , Biomarcadores , Doença Celíaca/diagnóstico , Doença Celíaca/terapia , Glutens , Humanos , Testes Sorológicos , Transglutaminases
19.
Sultan Qaboos Univ Med J ; 22(2): 262-267, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35673297

RESUMO

Objectives: This study aimed to estimate the serological prevalence of coeliac disease in patients with iron deficiency anaemia (IDA) of unknown cause at a primary healthcare facility in Oman. Methods: This prospective case-finding study was conducted at the primary care clinics in Sultan Qaboos University Hospital, Muscat, Oman from September 2018 to June 2020. Patients aged 18 to 55 years, with a haemoglobin (Hb) level <11.5 g/dL for males and <11.0 g/dL for females and a ferritin level <30 ng/mL for males and <13 ng/mL for females, were included in the study. Blood samples were obtained for initial serological screening using serum immunoglobulin (Ig)A level; those samples with normal levels of IgA, IgA anti-tissue transglutaminase antibody (tTG) and IgA anti-deamidated gliadin peptide (DGP) were determined. Positive IgA-tTG test was confirmed using IgA-endomysial antibodies. Patients with low IgA levels were tested using IgG-tTG and IgG-DGP. Results: A total of 104 patients participated in this study. Eight patients (7.7%) were found to have a positive serological screening result for coeliac disease; of these patients, three (37.5%) had a positive IgA-tTG result. Two of those three (66.7%) had a positive IgA-endomysial antibody. The IgA-DGP result was positive in seven (6.7%) of the 104 patients. Out of those seven patients, two also had a positive IgA tTG. Conclusion: Coeliac disease is not a rare disorder. There is a need to increase awareness among healthcare professionals about coeliac disease and its non-classical manifestations such as IDA.


Assuntos
Anemia Ferropriva , Doença Celíaca , Deficiências de Ferro , Adulto , Anemia Ferropriva/epidemiologia , Anemia Ferropriva/etiologia , Autoanticorpos , Doença Celíaca/complicações , Doença Celíaca/epidemiologia , Feminino , Gliadina , Humanos , Imunoglobulina A , Imunoglobulina G , Masculino , Prevalência , Transglutaminases
20.
Cells ; 11(12)2022 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-35741029

RESUMO

The lingual mucosa in birds is covered with two specific types of multilayered epithelia, i.e., the para- and orthokeratinized epithelium, that differ structurally and functionally. Comprehensive information on proteins synthesized in keratinocyte during their cytodifferentiation in subsequent layers of multilayered epithelia in birds concerns only the epidermis and are missing the epithelia of the lingual mucosa. The aim of the present study was to perform an immunohistochemical (IHC) and molecular analysis (WB) of bird-specific alpha-keratin, keratin-associated proteins (KAPs), namely filaggrin and loricrin, as well as transglutaminase 1 in the para- and orthokeratinized epithelium covering the tongue in the domestic duck, goose, and turkey. The results reveal the presence of alpha-keratin and KAPs in both epithelia, which is a sign of the cornification process. In contrast to the epidermis, the main KAPs involved in the cornification process of the lingual epithelia in birds is loricrin. Stronger expression with KAPs and transglutaminase 1 in the orthokeratinized epithelium than in the parakeratinized epithelium may determine the formation of a more efficient protective mechanical barrier. The presence of alpha-keratin, KAPs, and transglutaminase 1 epitopes characteristic of epidermal cornification in both types of the lingual epithelia may prove that they are of ectodermal origin.


Assuntos
Queratinas , Língua , Animais , Aves , Epitélio/metabolismo , Queratinas/metabolismo , Transglutaminases
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