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  • 1
    Electronic Resource
    Electronic Resource
    Amylase, cellulase and protease activities in surface and gut tissues ofDendraster excentricus, Pisaster ochraceus andStrongylocentrotus droebachiensis (Echinodermata) (1991)
    Springer
    Marine biology 109 (1991), S. 53-57 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In general, variance in tissue hydrolase (amylase, cellulase and protease) activity between individuals of a particular species is as great or greater than variance between tissue types or between species, e.g. although the specific activity of amylase in the gut tissue ofDendraster excentricus is significantly lower than that of aboral surface tissue, it is not significantly different than that of the oral surface tissue, or of the aboral surface of eitherPisaster ochraceus orStrongylocentrotus droebachiensis. Cellulase activity of the gut tissue ofS. droebachiensis was significantly higher than that of the gut tissue ofP. ochraceus andD. excentricus, reflecting the omnivorous feeding habit of the sea urchin. Cellulase activity of the gut tissue ofD. excentricus was not significantly higher than inP. ochraceus, an unexpected result, given the highly carnivorous behavior of the latter. Protease activity of the gut tissue ofD. excentricus is significantly higher than that of the oral or aboral surface tissues, but not significantly higher than that of the gut tissues ofP. ochraceus orS. droebachiensis. Amylase and cellulase activities in the guts of detritus- and shrimp-fedD. excentricus showed significant increases over that of field individuals; protease activity displayed no significant increase. Some significant surface (oral and aboral) changes were noted with respect to hydrolase activity, but the direction and lack of consistency of the changes argues that these are incidental to the process of digestion. The lack of significant differences in the surface enzyme activity ofD. excentricus, P. ochraceus andS. droebachiensis suggests that macronutrient digestive events in surface tissues are not uniquely important inD. excentricus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01320231
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  • 2
    Electronic Resource
    Electronic Resource
    The production and secreton of digestive enzymes in the purple seastar Pisaster ochraceus (1975)
    Springer
    Marine biology 29 (1975), S. 261-266 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The purple seastar Pisaster ochraceus contains clearly measurable protease and amylase activity. Centrifuged supernatants of pyloric caeca homogenates undergo a spontaneous threefold increase in protease activity when incubated under toluene for 50 h at 25°C. Amylase activity remains nearly constant over this period. Bovine trypsin at a 1 to 100 ratio (trypsin to supernatant protein) induces a twofold increase in protease activity over that of the control supernatant while having virtually no effect on amylase activity over the control. The data indicate a specific interaction of trypsin with a protease zymogen rather than a conspecific hydrolysis of membrane components or vesicles by trypsin. Two percent Triton X-100 used as a diluent in place of distilled, deionized water causes a sevenfold increase in protease activity and a twofold increase in amylase activity in pyloric caeca supernatants. The use of Triton as a diluent in the preparation of a stomach-tissue supernatant allows quantitative measurement of both protease and amylase activity in that tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00391852
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  • 3
    Electronic Resource
    Electronic Resource
    β-glucanase activity in the seastar Pisaster ochraceus (1995)
    Springer
    Marine biology 123 (1995), S. 735-740 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Specimens of Pisaster ochraceus, an intertidal carnivorous seastar, were collected in northern Puget Sound at Post Point, near Bellingham, Washington, USA, in November 1993, and used in experimentation through September 1994. Ammonium sulfate fractions (60% precipitates) from excised pyloric caeca (digestive glands) possessed β-glucanase activity directed toward such β-linked substrates as carboxymethylcellulose (CMC), partially-digested cellulose (cellodextrins) and the synthetic substrate p-nitrophenyl-β-D-glucoside (PNDG). pH-activity and pH-stability maxima were at pH 6 and 5, respectively. No hydrolytic activity was detectable on native cellulose, native chitin or on cationic-modified celluloses such as DEAE-cellulose. Gel filtration (Sephadex G-100) of this 60% precipitate followed by DEAE-Sephadex column chromatography revealed heterogeneity of β-glucanase activity, with an indication of up to 11 distinct fractions with variable activity directed toward the substrates indicated above (CMC, cellodextrins and PNDG). These fractions displayed differing ratios of hydrolytic activity on these substrates. None of the isolated fractions displayed activity toward either native cellulose or native chitin. Gut extracts from the edible mussel (Mytilus edulis), a common prey species of P. ochraceus, were shown to possess partially digested cellulose (cellodextrins). These cellodextrins were further degraded by seastar β-glucanases in vitro. The digestion of the gut contents of ingested prey provides a possible adaptive explanation for the presence of β-glucanase activity in a carnivore.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349116
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of feeding and starvation on proteolytic and tryptic activities in pyloric caecal tissues and duct fluids of the seastar Pisaster ochraceus (1985)
    Springer
    Marine biology 90 (1985), S. 55-59 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pisaster ochraceus were collected at Post Point, Bellingham, Washington, USA, in 1980. Total protease and tryptic specific activities were measured in pyloric caecal tissues and pyloric duct fluids of fed and starved individuals. Feeding resulted in increased levels of total protease and tryptic activities, and led to an increase in the ratio of total protease to tryptic specific activity in pyloric caecal tissue and a decrease in that ratio in pyloric duct fluid, indicating a release of trypsin into the duct with feeding. Trypsin activity showed little variability in fed seastars, but was quite variable in starving individuals. Total proteolytic acitivity, unlike that of tryptic activity, was always present in both fed and starved seastars. This way indicate a much broader role of generalized proteases in the cells of the pyloric caecum (e.g. as lysosomal enzymes of absorptive cells) in comparison to tryptic enzymes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00428214
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  • 5
    Electronic Resource
    Electronic Resource
    Isolation, purification and partial characterization of four digestive proteases from the purple seastar Pisaster ochraceus (1988)
    Springer
    Marine biology 97 (1988), S. 231-236 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An investigation of enzymatic activity in the pyloric caeca of Pisaster ochraceus collected at Post Point, Bellingham, Washington, USA, in 1982, revealed the presence of four distinct proteases. These enzymes have been partially purified and characterized and display tryptic, chymotryptic and carboxypeptidase A-like activity. The two distinctive tryptic enzymes have molecular weights of 88 000 and 25 200 daltons, respectively, as determined by reducting SDS-PAGE electrophoresis. The chymotryptic and carboxypeptidase A proteases have molecular weights of 22 800 and 34 400 daltons, respectively. The tryptic and chymotryptic enzymes are inactivated by phenylmethylsulfonyl fluoride, indicating that all are serine proteases. Both trypsins are inhibited by soybean trypsin inhibitor; however, the high molecular weight trypsin was not inhibited by tosyl-L-lysine chloromethyl ketone. The chymotrypsin was inhibited by tosyl-L-phenylalanine chloromethyl ketone. Both reagents indicate the involvement of histidine in the active site. The low molecular weight trypsin and the chymotrypsin were able to activate bovine trypsinogen to trypsin, as determined in a modified PAGE electrophoresis with trypsinogen and casein copolymerized in the gel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00391307
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  • 6
    Electronic Resource
    Electronic Resource
    A TREATISE ON THE USE OF EXPECTED VALUES IN WATER RESOURCE PROJECT EVALUATION (1969)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 5 (1969), S. 0 
    Details
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: This paper focuses on two factors that influence the acceptability of the expected value criterion as a method of handling risk or uncertainty in decision-making where damages from unusual physical occurrences such as hurricanes or floods must be considered. These are the length of time of project existence and the problem of obtaining accurate estimates of the probability of occurrence for different sizes of natural disasters. The problem of estimating accurate probabilities of occurrence for different sizes of natural disasters is not as great as it might appear and in most situations will not defeat the usefulness of the method. The time span during which the project is expected to exist has greater implications for the usefulness of the expected value approach appears highly applicable. However, it becomes less applicable for projects that are short-term in nature. The basis for distinguishing between short- and long-term projects is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1752-1688.1969.tb04901.x
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  • 7
    Electronic Resource
    Electronic Resource
    THE WATER RESOURCES COUNCIL'S PROPOSED PRINCIPLES AND STANDARDS - AN ECONOMIC COMMENT (1973)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 9 (1973), S. 0 
    Details
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: The way the Water Resources Council proposes to measure the beneficial effects of national economic development and recreation is questioned and alternatives suggested. In measuring the former, the assumptions specified by the Council are questioned because they do not hold true in the market place. In addition, the Council's method of simulating a price per recreation day implies that an arbitrary price be selected from a range and multiplied times the number of days at no charge for use of the facilities. It is contended that these procedures would over state the economic benefits which in the real market would be measured by the selected price times the quantity demanded at that price.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1752-1688.1973.tb01793.x
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  • 8
    Electronic Resource
    Electronic Resource
    A STUDY OF COASTAL POLLUTION AND AGENCY INTERFACE (1978)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 14 (1978), S. 0 
    Details
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: : The 26-mile man-made beach bordering part of Mississippi's Gulf Coast and the contiguous Mississippi Sound waters provide an important recreational and tourist attraction for that area. Being the tourist nucleus for the State, announcements in September 1973 by the Mississippi Air and Water Pollution Control Commission and the State Board of Health that Sound waters had reached a level of pollution that made them potentially dangerous for body contact was met with a myriad of responses. The resulting multi-governmental, multi-agency interface that resulted in trying to deal with the situation highlighted the type of problems that can arise when social, economic, political, and legal forces come to bear on a sensitive area. Questions of jurisdictional and legal authority to act, tourist industry economic pressures, and water quality testing and monitoring procedures were representative of the type of problems that arose during this period. A retrospective analysis of this problem served to isolate the type of articulation that is essential between federal, state, and local agencies vested with responsibilities such as monitoring water quality, protecting public health, etc. This paper develops some of the interface complexities that emerged in dealing with this problem and makes selected recommendations for other areas that may potentially face similar situations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1752-1688.1978.tb02255.x
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  • 9
    Electronic Resource
    Electronic Resource
    In vivo Effect of an Invasive Malignant Rat Tumour on Cartilage (1967)
    [s.l.] : Nature Publishing Group
    Nature 214 (1967), S. 1342-1343 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Sylvn et al.4-6 have also provided evidence that proteolytic enzymes, especially the cathepsins, may be released from viable malignant tumour cells. This release may be an integral part of the metabolism of these cells: the extracellular cathepsin activity probably accounts for much of their ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/2141342a0
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  • 10
    Electronic Resource
    Electronic Resource
    In vitro Evidence of Neutral Collagenase Activity in an Invasive Mammalian Tumour (1969)
    [s.l.] : Nature Publishing Group
    Nature 221 (1969), S. 259-260 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] In the experiments described here, undenatured acid-soluble collagen was used as a substrate for the demonstration of lytic activity in invasive tumour extracts. During these experiments, the characteristic degradation products of tropocollagen5 could be seen, electrophoretic-ally, and the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/221259a0
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