A micro-method for the quantitative estimation of rennets and other proteolytic enzymes

Anti-Deinagkistrodon acutus venom properties of ethanolic root extract from Cynanchum paniculatum (Bunge) kitag and its GC-MS analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Cynanchum paniculatum (Bunge) Kitag known as a popular Chinese herbal medicine has been used for a long time to treat a wide variety of diseases including snakebites. However, there is scarce information on the antiophidian potential of this plant.

AIM OF THE STUDY

The purpose of this work was to evaluate the inhibition effects of the ethanol extract of C. paniculatum on the enzymatic and biological activities induced by Deinagkistrodon acutus venom (DAV). The phytochemical components in the extract were also determined for understanding the mechanism of antivenom activities.

MATERIALS AND METHODS

Fresh root of C. paniculatum was shed-dried and smashed into powder. The powder was then extracted in 75% ethanol by refluxing method. Inhibition of proteolytic, phospholipase A₂, fibrinogenolytic and hyaluronidase activities of DAV by the extract were determined in vitro. Neutralization of lethal, hemorrhagic, myotoxic and edematogenic activities induced by the venom were also performed in vivo. Phytochemical constituents of the extract were analyzed by gas chromatography-mass spectrometry (GC-MS).

RESULTS

The ethanolic root extract of C. paniculatum (CPER) was able to completely (100%) inhibit protease and hyaluronidase activities induced by DAV when preincubated at a ratio of 1:100 and 1:50 (venom/extract, W/W), respectively. PLA₂ and fibrinogenolytic enzyme activities were actually neutralized at the concentration tested. In-vivo studies the inhibition of venom hemorrhagic and myotoxic action reached 100% when the venom was previously incubated with the extract (1:100) before injection. The edematogenic effect was also inhibited in a dose-response manner. CPER completely inhibited DAV-induced lethality in mice when the venom was preincubated with the extract at a ratio of 1:100. GC-MS analysis indicated that a total of 58 compounds were discovered in CPER. Among them, 5 bioactive constituents including 9,12-octadecadienoic acid (Z,Z)-, n-hexadecanoic acid, cis-vaccenic acid, γ-sitosterol and stigmasterol exhibit antivenom activity according to previous reports.

CONCLUSIONS

The results obtained in this work validate for the first time CPER as a traditional antiophidic herb, especially inhibitory effect on local damage induced by DAV, suggesting it could be used as a potential source of bioactive components against snakebites.

Detection of residual chymosin in cheese by an enzyme-linked immunosorbent assay

A simple and rapid competitive enzyme-linked immunosorbent assay method has been developed to detect the residual activity of chymosin in various types of cheese without extraction. In a cheese of the Saint-Paulin type, concentrations of chymosin detected at the end of cheesemaking in curd and whey represented 22·5 and 73·5% respectively of the total amount added to milk, so most of the chymosin was detected using this method. In a cooked pressed cheese of the Comté type, only 14% of the chymosin added to milk was detected in curd and all the chymosin in whey was inactivated. It was thus possible to demonstrate the presence of active residual chymosin in cooked pressed cheese. When measurements were carried out in 12 different cheeses, chymosin concentrations ranged between 384 ng/g in a Camembert cheese and 86 ng/g for an 8-month old Comté cheese. Chymosin appeared to be highly stable during cheese ripening.

Effect of salts addition on hydrogen production by C. acetobutylicum

The objective of this study is to investigate the effect of salts addition to fermentation medium on hydrogen production, under anaerobic batch culture system. In this study, batch experiments were conducted to investigate the inhibitory effect of both NaCl and sodium acetate on hydrogen production. The optimum pH and temperature for hydrogen production were at initial pH of 7.0 and 30 degrees C. Enhanced production of hydrogen, using glucose as substrate was achieved. In the absence of Sodium Chloride and Sodium Acetate enhanced hydrogen yield (Y(P/S)) from 350 mL g(-1) glucose utilized to 391 mL g(-1) glucose utilized with maximum hydrogen productivity of 77.5 ml/L/h. Results also show that sodium chloride and sodium acetate in the medium adversely affect growth. Hydrogen yield per biomass (Y(P/X)) of 254 ml/L/g, biomass per substrate utilized (Y(X/S)) of 0.268 and (Y(H2/S) of 0.0349. The results suggested that Sodium at any concentration resulted to inhibit the bacterial productivity of hydrogen.

Factors affecting the retention of rennet in cheese curd

The coagulant retained in cheese curd is a major contributor to proteolysis during ripening. The objective of this study was to quantify the effects of several milk-related factors and parameters during cheese manufacture on the retention of coagulant in cheese curd. The amount of coagulant retained in curd was determined by its activity on a synthetic heptapeptide (Pro-Thr-Glu-Phe-[NO2-Phe]-Arg-Leu) using reversed-phase HPLC. The retention of chymosin in cheese curd increased significantly when the pH of milk was reduced at rennet addition below pH 6.1, the pH at whey drainage below pH 5.7, or the average casein micelle size in milk and when the ionic strength of milk was increased. The casein content of milk and the quantity of chymosin added to milk had no significant effect on the retention of chymosin in curd; the quantity of coagulant bound per gram of casein remained unchanged.

Seminal pepsinogen C is not identical with, but is very similar to gastric pepsinogen C

Human seminal pepsinogen C has been purified and compared with gastric pepsinogen C. The two zymogens cannot be distinguished by amino acid compositions and sequences of the first 28 N-terminal amino acid residues are identical. Apparent immunological identity is observed with polyclonal antisera. Monoclonal antibodies toward seminal pepsinogen C have been produced. One is able to recognize a non-carbohydrate antigenic determinant only present in seminal pepsinogen C.

Simple screening method for identification of nonpleiotropic mutants for exoenzyme production

A differential medium that distinguishes between pleiotropic and nonpleiotropic mutants for exoenzyme production has been developed for Staphylococcus simulans biovar staphylolyticus. The medium will facilitate genetic analysis of exoenzyme production by this organism. Generally useful strategies for increasing the sensitivity of indicator plates for detection of exoenzyme activities are presented.

A sensitive fluorometric assay for the simultaneous estimation of pepsin and pepsinogen in gastric mucosa

An assay for pepsin has been developed based on the fluorometric measurement of trichloroacetic acid-soluble peptides released from casein at pH 5.3. The increase in relative fluorescence was most sensitive in the range 10-50 micrograms pepsin/l and casein hydrolysis was not affected by the addition of up to a 1000-fold molar excess of pepsinogen. This assay has been used to measure the free and total acid proteinase content of biopsies (less than 5 mg) from different areas of the gastric mucosa of rat and man. Interference by the major lysosomal acid hydrolase, cathepsin D, could be eliminated by the differential stability of pepsin and cathepsin D at acid and neutral pH. The free acid proteinase activity of biopsies from the corpus were almost identical in these species whereas the total acid proteinase activity was approximately 5-fold greater in man.

Gel diffusion--a simple and sensitive technique for the assay of proteinase inhibitors and its use for the determination of the ratio of proteinases in mixtures

In casein-containing agarose gels, pepsin and chymosin form radial diffusion zones; the diameters of these zones show rectilinear correlations with the logarithm of the enzyme concentration at constant time. The sensitivity for both enzymes is below 1 microgram. Addition of the inhibitor pepstatin A to these enzymes causes a reduction of the diameters of the diffusion zones, with large differences for both the enzymes. With this procedure, the pepsin/chymosin ratio in rennet preparations was assayed with an accuracy of +/- 5%. Identification of the inhibitors allows the determination of amounts in the namomole range. This method is a simple technique for the evaluation of proteinases and their inhibitors in screening systems.

Typing of Coagulase-Positive Staphylococci by Proteolytic Activity on Buffered Caseinate-Agar, with Special Reference to Bacteriophage Nontypable Strains

The specificities of the proteinases produced by 136 strains of coagulase-positive staphylococci on a buffered caseinate-agar medium at 37 C were investigated. Five well-defined groups of staphylococci could be differentiated by the patterns of precipitation zones obtained as a result of proteolysis. Within these five groups, slight variations in zone types were observed. The type of zone produced by any one strain was, however, highly reproducible, suggesting that the proteinases produced by staphylococci are strain-specific. Strains could be further differentiated by the patterns of precipitation obtained at 30 C. The differences in zone types on caseinateagar can be used as an adjunct to standard typing procedures, being particularly valuable in epidemiological investigations and in the differentiation of phage “non-typable” strains. In this survey, 63 of the strains investigated could not be typed by the international set of typing phages but could be readily differentiated in terms of their proteolytic activities at 37 and 30 C. No correlation was found between proteolytic activity, phage type, origin of the strains, or the production of enterotoxins A, B, or C.