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Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In vitro studies revealed that the hatching of oncospheres of Moniezia expansa requires the mechanical breakage of the eggshell and subshell membrane and enzymic digestion of the pyriform apparatus. Removal of the outer two egg membranes elicits the activation of most oncospheres. Between pH 5.0-7.8, there is no significant difference in numbers of oncospheres activated by eggshell removal and the addition of sodium bicarbonate has no effect. Solutions of more extreme pH values (2.0 and 10.0) are harmful and render oncospheres immobile. The subshell membrane forms a barrier to the passage of water in an osmotic gradient and to several molecular and ionic substances. Between the eggshell and subshell membrane is a layer of droplets which have a strong affinity for Sudan stains and which are partially removed by lipase. The eggshell is resistant to a variety of proteolytic enzymes, amylases and lipase. The pyriform apparatus is digested by chymotrypsin and pepsin, though not by trypsin. Both eggshell and pyriform apparatus are dissolved by solutions of sodium sulphide and sodium hypochlorite, indicating that their structures are stabilized by disulphide bonds and other covalent linkages.
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PMID:In vitro hatching of the tapeworm Moniezia expansa (Cestoda: Anoplocephalidae) and some properties of the egg membranes. 23 60

Antigens extracted from Cryptosporidium oocysts, which had been purified from faeces or chick egg culture, were electrophoresed in sodium dodecyl sulfate-polyacrylamide gels, and blotted onto nitrocellulose membranes. A Cryptosporidium genus-specific monoclonal antibody MAb-C1 bound to multiple bands using several detection techniques, and these corresponded to bands detected using immune rabbit antisera. Using a detection system with fluorescein isothiocyanate (FITC)-labelled MAb-C1 and alkaline phosphatase-labelled anti-FITC, bands were detected between 50 and 300 kDa. Blots were examined directly and by using a laser scanner. The system was shown to be specific for Cryptosporidium spp., giving no staining with a variety of other pathogens, and with negative samples. The oocyst antigen which bound MAb-C1 was stable, and banding patterns were not significantly affected by pretreatment of oocysts with proteinase K, trypsin, formalin, or sodium hypochlorite, methods commonly used during preparation and storage of C. parvum oocysts. However, banding was reduced with potassium dichromate. Of 76 samples containing Cryptosporidium oocysts, 53 showed one or more MAb-C1 staining bands. Cryptosporidium baileyi and C. parvum could be clearly differentiated by their banding patterns, indicating that the system will distinguish between species. Some isolates, including a single isolate of C. muris, produced weak bands which made interpretation difficult. The technique showed differences between isolates of C. parvum, with two different banding types found in human isolates, and other banding types seen in calf and lamb isolates. This method provides a useful way of characterising isolates which may be new species.
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PMID:A technique for typing Cryptosporidium isolates. 181 85

Studies on the in vitro excystation of Sarcocystis gigantea sporocysts revealed that pretreatment before exposure to trypsin and bile was an essential prerequisite. However, in contrast to Sarcocystis tenella and Sarcocystis capracanis, incubation in cysteine hydrochloride under CO2 was largely unsuccessful for excysting Sarcocystis gigantea: of the pretreatments tested, only exposure to sodium hypochlorite proved effective. Excystation from sodium hypochlorite-pretreated S. gigantea sporocysts took place in trypsin and bile between temperatures of 30 and 43 degrees C and occurred rapidly at 39 degrees C. While the presence of bile or bile salts was essential for this process, that of trypsin was not, although more sporocysts excysted in its presence than in its absence. Excystation occurred in the presence of all bile types tested but not when Tween 80 was substituted for bile. The highest levels of excystation were recorded when cattle or sheep bile or sodium taurocholate were used and the lowest when chicken or pig bile were employed. Neither the concentration of sheep bile above 2.5%, nor hydrogen ion concentration (pH range 5.0-10.0) appeared to have any marked effect on the level of excystation obtained.
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PMID:The in vitro excystation of Sarcocystis gigantea sporocysts. 212 59

Separation and recombination experiments were made with manually or trypsin-dissociated dental papillae (day 15, 16, 17, 18 in utero and 2, 7, 14 postnatal) and manually isolated hard tissues of the third molar crown (14 postnatal days). Several series of hard tissues were further treated with citric acid, hyaluronidase or sodium hypochlorite. The recombinations were transplanted into the subcutaneous tissue of new-born mice. Grafts were removed 7, 14 and 21 days later and prepared for light and electron microscopy. Whatever the age of the papilla and whatever the treatment of the crowns, well-characterized odontoblasts differentiated and deposited new layers of tubular dentine, except when the recombined dental papilla was 15 days old. These findings indicate that odontoblasts are very early committed (since day 16 in utero) and that they may differentiate in dental papillae in contact with chemically altered dentinal matrices.
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PMID:Differentiation of odontoblasts in mouse dental papillae recombined with normal or chemically-treated dentinal matrices. 228 4

1. Pretreatment of some proteins (albumin, immunoglobulin G, elastin and fibrinogen) with hypochlorite or with the MPO-H2O2-Cl- system increased their susceptibility to proteolysis by trypsin, chymotrypsin or elastase. 2. The optimal activities of these three proteinases were attained at a different extent of albumin chlorination. 3. Elastase was found to develop a specially efficient activity towards chlorinated albumin or chlorinated elastin being by itself resistant to chlorinating species.
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PMID:Enhancement of proteinase-mediated degradation of proteins modified by chlorination. 266 67

Extracted human deciduous teeth undergoing physiological root resorption were fixed with a mixture of formaldehyde and glutaraldehyde and processed for scanning (SEM) and analytical transmission electron microscopy, as well as acid trimetaphosphatase cytochemistry. The granulated tissues, which are rich in multinucleated odontoclasts and capillary vessels, formed various resorption lacunae on the resorbing dentin surfaces. SEM observations of dentin surfaces treated with sodium hypochlorite revealed two types of resorption lacunae: deep, round lacunae in which the peritubular matrix of dentinal tubules was strongly dissolved; and shallow, irregular lacunae with intact peritubular matrix. In trypsin-treated materials, the resorption surfaces were characterized by the presence of numerous collagen fibers in both the peritubular and intertubular matrices, suggesting demineralization of the surface dentin. Odontoclasts were characterized by the presence of abundant mitochondria, perinuclear stacks of Golgi membranes, various lysosomes, numerous endocytotic vacuoles, and a well-developed ruffled border against the resorption lacunae. Most endocytotic vacuoles were distributed in the cytoplasm between the ruffled border and the nuclei. In undemineralized ultrathin sections, the surface dentin of resorption lacunae consisted of collagen fibers and apatite crystals and had a lower packing density than those in unresorbed, deeper dentin. Many apatite crystals were demonstrated to be present in the extracellular channels of the ruffled border and in adjacent endocytotic vacuoles derived from it. Lysosomes located in the perinuclear cytoplasm of odontoclasts contained amorphous dense material and/or a small amount of crystals. An energy-dispersive x-ray microanalysis of apatite crystals in undemineralized sections indicated that the energy spectrum peaks of Ca and P detected from crystals in resorbing dentin were much lower than those in unresorbed dentin. Similarly, lower spectrum peaks of Ca and P were obtained from crystals found in the ruffled border and endocytotic vacuoles of odontoclasts. A slight trace Ca peak also was detected in the amorphous dense material in lysosomes of odontoclasts. The enzyme cytochemistry of lysosomal acid trimetaphosphatase indicated that odontoclasts had intense enzymatic activity in the Golgi membranes, endoplasmic reticulum cisternae, lysosomes, and endocytotic vacuoles. Dense reaction precipitates of enzymatic activity also were found along the dentin surfaces of resorption lacunae occupied by odontoclast ruffled borders.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Dentin resorption mediated by odontoclasts in physiological root resorption of human deciduous teeth. 285 Dec 63

Improved rates of in vitro excystation of sporozoites from sporocysts of Sarcocystis capracanis, Sarcocystis cruzi, and Sarcocystis tenella were obtained by pretreating sporocysts with an aqueous sodium hypochlorite (NaOCl) solution followed by incubation in excysting fluid (EF). After pretreatment with NaOCl, sporocysts were washed 4 times in Hanks' balanced salt solution and then incubated in various EF (pH 7.4) at 38.5 C in 5% CO2-95% air. Maximum rates of excystation (free sporozoites/(sporozoites in sporocysts + free sporozoites) X 100) for all 3 species of Sarcocystis occurred at 4 hr after incubation in EF. These rates were 17% for S. capracanis after incubation in EF containing 2% trypsin + 10% caprine bile; 90% for S. cruzi in 2% trypsin + 10% bovine bile; and 20% for S. tenella in 2% trypsin + 10% caprine bile. Only a 40% excystation rate occurred in sporocysts of S. cruzi that had been stored previously for 14 days in aqueous potassium dichromate. Excysted sporozoites of S. capracanis, S. cruzi, and S. tenella penetrated and developed to mature meronts in bovine pulmonary artery endothelial cells or bovine monocytes.
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PMID:In vitro excystation of Sarcocystis capracanis, Sarcocystis cruzi and Sarcocystis tenella (Apicomplexa). 310 13

The in vitro excystation of sporozoites of Isospora suis Biester 1934 is described. Sporocysts of I. suis lack a Stieda body. Upon incubation in 0.75% sodium taurocholate or in 0.25% trypsin + 0.75% sodium taurocholate excystation solutions, sporozoites were released by separation of the sporocyst wall into four plates. Occasionally, the sporocyst wall did not separate completely but opened partially and released the sporozoite. At the time of excystation, sporozoites were short and broad but became elongated after 5 to 10 min in the excystation fluids. Elongate sporozoites measuring 11.7 x 3.8 micrometers, had a pointed anterior end and a nucleus located in the posterior half of the cell. Living sporozoites exhibited gliding movements, side-to-side flexion, and probed with their anterior ends. Incubation in 5.25% sodium hypochlorite removed the oocyst walls from most oocysts. Sporozoites did not excyst from sporocysts that were released during treatment with sodium hypochlorite.
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PMID:Excystation of Isospora suis Biester, 1934 of swine. 683

Spores of Bacillus piliformis of rabbit origin were harvested from the yolk sac of previously inoculated hen's eggs and subjected to various heat or chemical disinfectant treatments. Subsequently, spores were tested for infectivity in embryonated eggs inoculated via the yolk sac route, and others were treated with trypsin and then tested in embryonated eggs. The spores were not affected by the heat treatment of 60 degrees C but were rendered noninfective with treatments of 70 degrees C and 80 degrees C. Infectivity was not restored by treatment with trypsin. Infectivity was not lost when spores were treated with a phenolic germicidal detergent, ethanol or either of two quaternary ammonium compounds containing 9% or 17% benzalkonium chloride. A graded effect was observed with formaldehyde solution and an iodophor. Spores were rendered noninfective after treatment with peracetic acid (1.0%) and a wetting agent, sodium alkylarylsulfonate or sodium hypochlorite solution (0.3%) for 5 minutes, and infectivity was not restored by trypsin treatment. The probable means of transmission of Bacillus piliformis was discussed and sodium hypochlorite solution (0.3%) was recommended as a surface disinfectant in animal facilities as an aid to the prevention and control of Tyzzer's disease.
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PMID:Effect of heat and selected chemical disinfectants upon infectivity of spores of Bacillus piliformis (Tyzzer's disease). 705 74

Studies on the activation and excystation of I. felis and I. rivolta sporozoites revealed that, although some differences were apparent between the two, both were capable of activation under a wide range of conditions. Activation of both species took place in trypsin and bile between 21 and 43 C (the range tested) occurring rapidly at 39 C. Although the presence of bile appeared to be essential for this process that of trypsin did not. Neither the concentration of bile (above 5%), the type of bile, nor the hydrogen ion concentration had a marked effect on the level of activation. Pretreatment of oocysts in aqueous cysteine hydrochloride under CO2 or with sodium hypochlorite before exposure to trypsin and bile was not an essential prerequisite for the activation of I. felis and I. rivolta. However, higher levels of activation were attained when pretreatment was used. But for I. rivolta, the level of activation appeared to be less dependent on pretreatment for oocysts stored in sulfuric acid than for those stored in potassium dichromate. The process of activation and excystation of both species was essentially similar to that described for other species of disporocystic coccidia with heteroxenous life cycles. Sporozoites escaped following the collapse of the sporocyst wall and completed excystation through indentations and fractures at one or both ends of the oocyst.
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PMID:Activation and excystation of Isospora felis and Isospora rivolta sporozoites. 707 58


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