Consumption of kiwifruit has long been claimed anecdotally to assist in gastric digestion. This has generally been assumed to be due to the presence of the proteolytic enzyme actinidin; however, ...there is little published evidence supporting this assumption. This paper reports the findings of an in vitro study that examined the effect of kiwifruit proteases (actinidin) on the digestion of a range of common food proteins under simulated gastric conditions. An extract from green kiwifruit containing actinidin was prepared. Several protein sources derived from soy, meat, milk, and cereals were incubated in the presence or absence of the kiwifruit extract using an in vitro digestion system consisting of incubation with pepsin at pH 1.9, simulating gastric digestion in humans. The digests were subjected to gel electrophoresis (SDS-PAGE). For some protein sources, simulated digestion in the presence of kiwifruit extract resulted in a substantially greater loss of intact protein and different peptide patterns from those seen after digestion with pepsin alone. As an example, the addition of actinidin extract enhanced the digestion of α-, β-, and κ-caseins in sodium caseinate by 37, 33, and 48%, respectively. Under simulated gastric conditions, kiwifruit extract containing actinidin enhanced the digestion of some, but not all, food proteins over and above that found with pepsin alone.
This paper describes an in vitro study that tests the proposition that actinidin from green kiwifruit influences the digestion of proteins in the small intestine. Different food proteins, from ...sources including soy, meat, milk, and cereals, were incubated in the presence or absence of green kiwifruit extract (containing actinidin) using a two-stage in vitro digestion system consisting of an incubation with pepsin at stomach pH (simulating gastric digestion) and then with added pancreatin at small intestinal pH, simulating upper tract digestion in humans. The digests from the small intestinal stage (following the gastric digestion phase) were subjected to gel electrophoresis (SDS-PAGE) to assess loss of intact protein and development of large peptides during the in vitro simulated digestion. Kiwifruit extract influenced the digestion patterns of all of the proteins to various extents. For some proteins, actinidin had little impact on digestion. However, for other proteins, the presence of kiwifruit extract resulted in a substantially greater loss of intact protein and different peptide patterns from those seen after digestion with pepsin and pancreatin alone. In particular, enhanced digestion of whey protein isolate, zein, gluten, and gliadin was observed. In addition, reverse-phase HPLC (RP-HPLC) analysis showed that a 2.5 h incubation of sodium caseinate with kiwifruit extract alone resulted in approximately 45% loss of intact protein.
Genetic Variation in Pea Seed Globulin Composition Tzitzikas, Emmanouil N; Vincken, Jean-Paul; de Groot, Jolan ...
Journal of agricultural and food chemistry,
01/2006, Letnik:
54, Številka:
2
Journal Article
Recenzirano
A quantitative characterization of seeds from 59 pea (Pisum sativum L.) lines and relative taxa with various external characteristics and wide geographical origin was performed to explore the genetic ...variation of pea concerning its starch and protein contents and globulin composition. Pea lines, which produce round, wrinkled, flat, and round-dimpled seeds, have starch as the major reserve, with an average content of 46%. Protein content varied from 13.7 to 30.7% of the seed dry matter, with an overall average of 22.3%. Densitometric quantification of the individual globulins (legumin, vicilin, convicilin, and globulin-related proteins) based on SDS-PAGE gels showed no lines lacking any particular globulin. Among the lines tested, variation was shown in both their total globulins content and their globulin composition. The total globulin content ranged from 49.2 to 81.8% of the total pea protein extract (TPPE). Legumin content varied between 5.9 and 24.5% of the TPPE. Vicilin was the most abundant protein of pea, and its content varied between 26.3 and 52.0% of the TPPE. Both processed and nonprocessed vicilins occurred. The processed vicilin was the predominant one, with values between 17.8 and 40.8%, whereas the nonprocessed ones constituted between 3.1 and 13.5% of the TPPE. Convicilin was the least abundant globulin, and its content ranged from 3.9 to 8.3%. Finally, the globulin-related proteins were present in amounts ranging from 2.8 to 17.3%. They were less abundant in comparison with legumin and vicilin, but they showed the largest relative variation of the four globulin classes. Correlations between the different external characteristics and globulin composition were determined. Comparison with soybean showed that pea lines show more variety in the abundance of globulin proteins, enabling a wider range of food application. Keywords: Peas; Pisum sativum L.; globulins; vicilin; convicilin; legumin; seed proteins; SDS−polyacrylamide gel electrophoresis; in vivo processing
You-gui Pill (YGP), a traditional Chinese medicinal prescription, was widely used to warm and recuperate “kidney-yang” clinically for hundreds of years in China. Recent studies found that YGP had a ...potential benefit for renoprotection.
The present study aimed to elucidate the in vivo and in vitro efficacy of YGP on renal tubulointerstitial fibrosis, and the molecular mechanism is also investigated.
Rat renal tubulointerstitial fibrosis model was elicited by unilateral ureteral obstruction (UUO). Sprague–Dawley rats underwent UUO and were studied after 14 days. Animals were randomly subjected to six groups: sham, UUO, UUO/YGP (0.14, 0.42, 1.26g/kg/d), and UUO/enalapril (10mg/kg/d). HE, Masson and ELISA were used for evaluate renal injury and function. Immunohistochemical analysis and western blot were used to detect the expressions of α-SMA, fibronectin, collagen matrix and Smads. In vitro studies were investigated in TGF-β1-stiumlated NRK-49F cell line.
Oral administration of YGP significantly decreased UUO-induced inflammatory cell infiltration, tubular atrophy and interstitial fibrosis, and there was no significant difference between YGP at 1.26g/kg and enalapril at 10mg/kg treatment (P>0.05). Meanwhile, serum creatinine and blood urea nitrogen levels were reduced dramatically (P<0.01). In coincide with the decreased of TGF-β1, α-SMA, fibronectin and collagen matrix expressions were also declined with YGP treatment in both UUO kidneys and TGF-β1-stimulated NRK-49F cell line. Additionally, nuclear translocation of p-Smad2/3 was markedly down-regulated by YGP (P<0.001), with a relative mild up-regulated expression of Smad7 (P<0.05).
Our findings demonstrate that YGP had a renoprotective effect in ameliorating renal tubulointerstitial fibrosis, and this activity possibly via suppression of the TGF-β and its downstream regulatory signaling pathway, including Smad2/3.
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In the nowadays mainly mass spectrometry-driven world of Proteomics, one can frequently read and hear that 2D gel-based electrophoresis methods are no longer used for proteome analysis. This short ...review is a compilation of facts why the gel-based workflow is not dead.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Natural antisense transcripts (NATs) as one of the most diverse classes of long noncoding RNAs (lncRNAs), have been demonstrated involved in fundamental biological processes in human. Here, we ...reported that human prohibitin gene pseudogene 1 (PHBP1) was upregulated in ESCC, and increased PHBP1 expression in ESCC was associated with clinical advanced stage. Functional experiments showed that PHBP1 knockdown inhibited ESCC cells proliferation, colony formation and xenograft tumor growth in vitro and in vivo by causing cell-cycle arrest at the G1-G0 phase. Mechanisms analysis revealed that PHBP1 transcript as an antisense transcript of PHB is partially complementary to PHB mRNA and formed an RNA-RNA hybrid with PHB, consequently inducing an increase of PHB expression at both the mRNA and protein levels. Furthermore, PHBP1 expression is strongly correlated with PHB expression in ESCC tissues. Collectively, this study elucidates an important role of PHBP1 in promoting ESCC partly via increasing PHB expression.
► We investigated transglutaminase polymerisation of brown rice proteins in the flour and in the isolated protein fractions. ► Glutelin complexes polymerise into new supramolecular structures, while ...albumins and globulins are only slightly affected. ► The major glutelin subunits are primary substrates for the cross-linking reaction. ► The newly formed supramolecular complexes are the result of covalent bonds as well as strong hydrophobic interactions. ► The newly formed complexes and interactions explain in molecular terms the improved textural quality of brown rice breads.
Recently, it was shown that transglutaminase (TGase) treatment of brown rice (BR) flour results in textural improvements of gluten-free bread. In this study, changes in the protein profiles of BR flour and protein fractions induced by TGase treatment were investigated to better understand the activity and specificity of the enzyme. Size-exclusion HPLC (SE-HPLC) profiles of flour extracts, under reducing conditions, revealed the presence of macromolecular protein complexes, as well as low molecular weight proteins. After TGase treatments (10U/g of proteins) a general reduction in peak intensities indicated the polymerisation of BR proteins into larger, insoluble complexes. Microchip capillary electrophoresis and two-dimensional (2D) gel electrophoresis revealed that the α and β glutelin subunits were primary substrates for the polymerisation reaction, whereas albumins and globulins were only slightly affected. SE-HPLC of the protein fractions revealed glutelins’ polymerisation into high molecular weight structures after TGase treatment. Dynamic light scattering measurements showed that new supramolecular aggregates of glutelins co-existed with the macromolecular complexes already present in the untreated fraction. Front-face fluorescence approaches indicated that TGase treatment caused a decrease in protein surface hydrophobicity of BR flour, but not of the glutelin suspensions. It is concluded that the large protein complexes resulting from glutelin polymerisation and the stronger hydrophobic interactions among proteins result in the improved textural properties of TGase-treated BR bread.
Exposure to limiting oxygen in cells and tissues induce the stabilization and transcriptional activation of the hypoxia-inducible factor 1 alpha (HIF-1α) protein, a key regulator of the hypoxic ...response. Reactive oxygen species (ROS) generation has been implicated in the stabilization of HIF-1α during this response, but this is still a matter of some debate. In this study we utilize a mitochondria-targeted antioxidant, mitoubiquinone (MitoQ), and examine its effects on the hypoxic stabilization of HIF-1α. Our results show that under conditions of reduced oxygen (3% O
2), MitoQ ablated the hypoxic induction of ROS generation and destabilized HIF-1α protein. This in turn led to an abrogation of HIF-1 transcriptional activity. Normoxic stabilization of HIF-1α, on the other hand, was unchanged in the presence of MitoQ suggesting that ROS were not involved. This study strongly suggests that mitochondrial ROS contribute to the hypoxic stabilization of HIF-1α.
Abstract
Separating proteins according to two different gel-electrophoretic methods not only increases the resolution power for highly complex samples when compared to one-dimensional separations, ...but is also a valuable tool for protein and protein complex characterization. There are a number of different electrophoresis methods which can be combined. The combination of isoelectric focusing under denaturing conditions and SDS polyacrylamide gel electrophoresis delivers the highest resolution of all bio-analytic techniques. This is a short review on the history and state of the art of two-dimensional electrophoresis methods, and contains some practical tips for high resolution 2D electrophoresis, which are based on several decades of experience with this method.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Edwardsiella tarda is a causative agent of edwardsiellosis in freshwater and marine fish. Extracellular enzymic, haemolytic, hydrophobic and serum resistance activities, haemagglutination, ...autoagglutination and siderophores of high‐ and low‐ virulent E. tarda strains were examined. The results revealed different haemagglutination, autoagglutination, haemolytic, hydrophobic and serum resistance activities in different strains. Analysis of extracellular proteins (ECPs) and outer membrane proteins (OMPs) demonstrated several major, low molecular weight, virulent‐strain‐specific proteins, which could be virulence‐related. Based on the database search with MALDI‐TOF MS data, the closest homologies of the three protein bands Ed1, Ed2 and Ed3 were phosphotransferase enzyme family protein, nitrite reductase NAD(P)H, large subunit and ATP‐dependent Lon protease, respectively. A comparison of pathogenicity of purified lipopolysaccharide (LPS) and lipid A from virulent and avirulent strains demonstrated that LPS was one of the virulence factors of the E. tarda isolates, and lipid A was a biologically active determinant of LPS.
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