The pepsins of normal human gastric juice.
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ABSTRACT:
SUBMITTER: Etherington DJ
PROVIDER: S-EPMC1184747 | biostudies-other | 1969 Jul
REPOSITORIES: biostudies-other
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Project description:1. The pepsins and pepsinogens of the gastric mucosal extracts of two normal subjects, of seven patients with gastric adenocarcinoma and of two patients with duodenal ulcer have been investigated by agar-gel electrophoresis and by ion-exchange chromatography. 2. Of the eight zones of proteolytic activity that have previously been reported in normal human gastric juice, seven can be detected in activated fundic mucosal extracts. Of these seven, four can be attributed to discrete pepsins, numbered 1, 3a, 3 and 5. 3. Zone 7 results from the activity of one or more enzymes that are alkali-stable and are best referred to as gastric proteinases rather than as pepsins. Zone 7 is much more evident in mucosal extracts than in gastric juice. 4. Zones 4 and 6 may result respectively from the activity of a pepsin-inhibitor complex and of an unactivated zymogen. 5. It was not possible, by the chromatographic methods employed, to separate satisfactorily the individual pepsins from activated extracts or their precursors from unactivated extracts, so that the ascribing of a pepsin to a specific zymogen must be considered tentative. Even so, pepsin 3 appears to arise from at least two major precursors, if not from three, whereas pepsins 1 and 5 each arise from a single major precursor. 6. Pyloric mucosal extracts contain principally zone 5 but also zones 6 and 7. These zones in general behave similarly to the corresponding zones of fundic extracts, but pyloric pepsin 5 migrates slightly faster on agar-gel electrophoresis than does fundic pepsin 5 and is a different enzyme. Zones 1 to 4 are absent.
| S-EPMC1179255 | biostudies-other
Project description:A glycopeptide containing 69% carbohydrate was isolated from human gastric juice. The complex was found to be homogeneous and to have mol.wt. 9600. The glycopeptide consisted of a protein core to which were linked, by O-glycosidic linkages to threonine and N-glycosidic linkages, carbohydrate side chains composed of N-acetylgalactosamine, N-acetylglucosamine, galactose, mannose, fucose and sialic acid, in the proportions 2:10:7:4:12:1.
| S-EPMC1164674 | biostudies-other
Project description:Gastritis Gastric Juice Shotgun Digest
2010-09-02 | PRD000212 | Pride
Project description:Extracellular vesicles (EVs) are secretory membrane vesicles containing lipids, proteins, and nucleic acids; they function in intercellular transport by delivering their components to recipient cells. EVs are observed in various body fluids, i.e., blood, saliva, urine, amniotic fluid, and ascites. EVs secreted from cancer cells play important roles in the formation of their environment, including fibrosis, angiogenesis, evasion of immune surveillance, and even metastasis. However, EVs in gastric juice (GJ-EVs) have been largely unexplored. In this study, we sought to clarify the existence of GJ-EVs derived from gastric cancer patients. GJ-EVs were isolated by the ultracentrifuge method combined with our own preprocessing from gastric cancer (GC) patients. We verified GJ-EVs by morphological experiments, i.e., nanoparticle tracking system analysis and electron microscopy. In addition, protein and microRNA markers of EVs were examined by Western blotting analysis, Bioanalyzer, or quantitative reverse transcription polymerase chain reaction. GJ-EVs were found to promote the proliferation of normal fibroblast cells. Our findings suggest that isolates from the GJ of GC patients contain EVs and imply that GJ-EVs partially affect their microenvironments and that analysis using GJ-EVs from GC patients will help to clarify the pathophysiology of GC.
| S-EPMC6412909 | biostudies-literature
Project description:Simple Summary Gastric cancer (GC) is one of the most common cancers and the fifth leading cause of cancer-related deaths worldwide. The steadily growing interest in secreted extracellular vesicles (EVs) is related to their ability to carry a variety of biologically active molecules, which can be used as markers for liquid noninvasive diagnosis of malignant neoplasms. For these applications, blood is the most widely used source of EVs. However, this body fluid contains an extremely heterogeneous mixture of EVs originating from different types of normal cells and tissues. The aim of this study was to assess the possibility of using gastric juice (GJ) as an alternative source of EVs since it is expected to be enriched in vesicles of tumor origin. We validated the presence of EVs in GJ using transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and western-blot analysis of exosomal markers, showed for the first time the feasibility of their isolation by ultracentrifugation and demonstrated the prospect of using GJ-derived EVs as a source of GC miRNA markers. Abstract EVs are involved in local and distant intercellular communication and play a vital role in cancer development. Since EVs have been found in almost all body fluids, there are currently active attempts for their application in liquid diagnostics. Blood is the most commonly used source of EVs for the screening of cancer markers, although the percentage of tumor-derived EVs in the blood is extremely low. In contrast, GJ, as a local biofluid, is expected to be enriched with GC-associated EVs. However, EVs from GJ have never been applied for the screening and are underinvestigated overall. Here we show that EVs can be isolated from GJ by ultracentrifugation. TEM analysis showed high heterogeneity of GJ-derived EVs, including those with exosome-like size and morphology. In addition to morphological diversity, EVs from individual GJ samples differed in the composition of exosomal markers. We also show the presence of stomatin within GJ-derived EVs for the first time. The first conducted comparison of miRNA content in EVs from GC patients and healthy donors performed using a pilot sampling revealed the significant differences in several miRNAs (-135b-3p, -199a-3p, -451a). These results demonstrate the feasibility of the application of GJ-derived EVs for screening for miRNA GC markers.
| S-EPMC9318556 | biostudies-literature
Project description:Plasmepsins are a group of diverse aspartic proteases in the malaria parasite Plasmodium Their functions are strikingly multifaceted, ranging from hemoglobin degradation to secretory organelle protein processing for egress, invasion, and effector export. Some, particularly the digestive vacuole plasmepsins, have been extensively characterized, whereas others, such as the transmission-stage plasmepsins, are minimally understood. Some (e.g. plasmepsin V) have exquisite cleavage sequence specificity; others are fairly promiscuous. Some have canonical pepsin-like aspartic protease features, whereas others have unusual attributes, including the nepenthesin loop of plasmepsin V and a histidine in place of a catalytic aspartate in plasmepsin III. We have learned much about the functioning of these enzymes, but more remains to be discovered about their cellular roles and even their mechanisms of action. Their importance in many key aspects of parasite biology makes them intriguing targets for antimalarial chemotherapy. Further consideration of their characteristics suggests that some are more viable drug targets than others. Indeed, inhibitors of invasion and egress offer hope for a desperately needed new drug to combat this nefarious organism.
| S-EPMC7307202 | biostudies-literature
Project description:Polysaccharide material was found in the proteolysis glycopolypeptide fraction from normal human gastric mucus. The polysaccharide was identified by carbohydrate and amino acid analyses, by elemental analysis and from its behaviour on density-gradient ultracentrifugation. The polysaccharide is polydisperse with a weight-average molecular mass of 300 000 Da. Over 85% of the polysaccharide consists of galactose, and this represents 26% of all the galactose present in the fractions after beta-elimination with reduction of the glycopolypeptide material.
| S-EPMC1152412 | biostudies-other
Project description:Gastric Juice Microbiota
| PRJEB65865 | ENA
Project description:BackgroundThe occurrence and development of gastric cancer are related to microorganisms, which can be used as potential biomarkers of gastric cancer.ObjectiveTo screen the microbiological markers of gastric cancer from the microorganisms of gastric juice.MethodsGastric juice samples were collected from 61 healthy people and 78 patients with gastric cancer (48 cases of early gastric cancer and 30 cases of advanced gastric cancer). The bacterial 16 S rRNA V1-V4 region of gastric juice samples was sequenced. The Shannon index, Simpson index, Ace index and Chao index were used to analyze the diversity of gastric juice samples. The RDP classifier Bayesian algorithm was used to analyze the community structure of 97% OTU representative sequences with similar levels. Linear discriminant analysis and ST-test were used to analyze the differences. Six machine learning algorithms, including the logistic regression algorithm, random forest algorithm, neural network algorithm, support vector machine algorithm, Catboost algorithm and gradient lifting tree algorithm, were used to construct risk prediction models for gastric cancer and advanced gastric cancer.ResultsThe microbiota diversity and the abundance of bacteria was different in the healthy group, early gastric cancer and advanced gastric cancer (P < 0.05). The top five abundant bacteria among the three groups were Streptococcus, Rhodococcus, Prevotella, Pseudomonas and Helicobacter. Bacterial flora such as Streptococcus, Rhodococcus and Ochrobactrum were significantly different between the healthy group and the gastric cancer group. The accuracy of the random forest prediction model is the highest (82.73% correct). The bacteria with the highest predictive value included Streptococcus, Lactobacillus and Ochrobactrum. The abundance of bacteria such as Fusobacterium, Capnocytophaga, Atopobium, Corynebacterium was high in the advanced gastric cancer group.ConclusionGastric juice bacteria can be used as potential biomarkers to predict the occurrence and development of gastric cancer.
| S-EPMC9860007 | biostudies-literature
Project description:Nucleic acids (NAs) were recently shown to be digested by pepsin in vitro; however, NAs digestion in human gastric juice in vivo is more complicated because of the complex gastric environment and ingestion of other food components. The purpose of this study was to investigate the digestibility of NAs in real human gastric juices after ingestion of other food components. As a result, DNA digestion was not affected when carbohydrates, proteins, and metal elements were ingested within the recommended dietary intake levels. Separately, protein exerted an inhibitory effect on DNA digestion when the mass ratio of protein:DNA was greater than 40:1. DNA exists in the nucleoprotein, which is closer to the state of DNA in real food, and was digested efficiently in human gastric juice. Meanwhile, DNA digestion was rarely affected even when the concentrations of monovalent ion (Na+) and divalent ions (Mg2+) were as high as 500 and 100 mM, respectively, and high concentration of Mg2+ ranged from 20 to 100 mM accelerated the digestion. In particular, short-stranded DNA (<100 nt) and miRNAs (19 ~ 25 nt) were not obviously degraded in human gastric juice. In conclusion, dietary NAs were digested efficiently and were not affected by other food components in human gastric juice, which may facilitate further digestion and utilization of DNA in the intestinal tract.
| S-EPMC10563756 | biostudies-literature