Naturally Occurring Inhibitors and Lysins in Various Centrifugally Prepared Fractions of Adult and Fetal Guinea Pig Tissue Extracts

1951 ◽  
Vol 164 (2) ◽  
pp. 467-475 ◽  
Author(s):  
David B. Tyler
Keyword(s):  
Guinea Pig ◽  
Tissue Extracts ◽  
Naturally Occurring

scholarly journals Hydrolysis of a naturally occurring β-glucoside by a broad-specificity β-glucosidase from liver

1986 ◽  
Vol 237 (2) ◽  
pp. 469-476 ◽  
Author(s):  
K L LaMarco ◽  
R H Glew
Keyword(s):  
Guinea Pig ◽  
Competitive Inhibitor ◽  
Heat Denaturation ◽  
Pig Liver ◽  
Naturally Occurring ◽  
Aryl Glycosides ◽  
Beta Glucosidase ◽  
Hydrolysis Of ◽  
Guinea Pig Liver ◽  
Broad Specificity

We have isolated from guinea-pig liver a broad-specificity beta-glucosidase of unknown function that utilizes as its substrate non-physiological aryl glycosides (e.g. 4-methylumbelliferyl beta-D-glucopyranoside, p-nitrophenyl beta-D-glucopyranoside). The present paper documents that this enzyme can be inhibited by various naturally occurring glycosides, including L-picein, dhurrin and glucocheirolin. In addition, L-picein, which acts as a competitive inhibitor of the broad-specificity beta-glucosidase (Ki 0.65 mM), is also a substrate for this enzyme (Km 0.63 mM; Vmax. 277,000 units/mg). Heat-denaturation, kinetic competition studies, chromatographic properties and pH optima all argue strongly that the broad-specificity beta-glucosidase is responsible for the hydrolysis of both the non-physiological aryl glycosides and L-picein. This paper demonstrates that beta-glucosidase can catalyse the hydrolysis of a natural glycoside, and may provide a key to understanding the function of this enigmatic enzyme. A possible role in the metabolism of xenobiotic compounds is discussed.

scholarly journals Naturally Occurring Parelaphostrongylus tenuis–Associated Choriomeningitis in a Guinea Pig With Neurologic Signs

2012 ◽  
Vol 50 (3) ◽  
pp. 560-562 ◽  
Author(s):  
T. Southard ◽  
H. Bender ◽  
S. E. Wade ◽  
C. Grunenwald ◽  
R. W. Gerhold
Keyword(s):  
Guinea Pig ◽  
Naturally Occurring ◽  
Parelaphostrongylus Tenuis

scholarly journals THE OCCURRENCE AND DISTRIBUTION OF ATROPINESTERASE, AND THE SPECIFICITY OF TROPINESTERASES

1941 ◽  
Vol 25 (2) ◽  
pp. 197-205 ◽  
Author(s):  
David Glick ◽  
Susi Glaubach
Keyword(s):  
Guinea Pig ◽  
Egg White ◽  
Pig Liver ◽  
Naturally Occurring ◽  
Hydrolysis Of ◽  
Guinea Pig Liver

Atropinesterase was found to exist in approximately one out of every four rabbits, and no relation could be observed between the incidence of the enzyme and season, sex, color, age, or weight. The occurrence of the enzyme was also shown to be unrelated to that of cholinesterase. The distribution of atropinesterase in the blood and organs of rabbits was studied; the animals devoid of the enzyme in their blood contained no demonstrable activity in any of the organ extracts tested. The presence of atropinesterase in frog liver, and its absence from the serum, has been confirmed. Hydrolysis of homatropine, but not atropine, by guinea pig liver was observed, while the serum was without action on either of the compounds. On this basis the possibility arises that guinea pig liver contains a homatropinesterase enzyme separate from atropinesterase. It was shown that lack of atropinesterase activity in certain rabbits is not likely to be due to the presence of a naturally occurring inhibitor. It has been demonstrated that contrary to previous indications neither fresh egg white nor yolk possess atropinesterase activity. The specificity of tropinesterases was investigated and evidence was presented for the possible existence of two distinct enzymes, cocainesterase and tropacocainesterase.

The effects of various pharmacological agents on the distribution of antihistamine activity of rat tissue extracts

1969 ◽  
Vol 47 (9) ◽  
pp. 755-762 ◽  
Author(s):  
M. Lefcort ◽  
L. E. Francis ◽  
K. I. Melville
Keyword(s):  
Mast Cell ◽  
Guinea Pig ◽  
Rat Tissues ◽  
Guinea Pig Ileum ◽  
Pharmacological Agents ◽  
Abdominal Skin ◽  
Tissue Extracts ◽  
Antihistamine Activity ◽  
Rat Tissue ◽  
Different Tissues

Extracts of rat tissues (ear and abdominal skin, heart, cerebrum, spleen, kidney, lung, liver, stomach, and jejunum) were tested for their ability to antagonize histamine on the guinea pig ileum preparation. Antihistamine activity varied considerably between tissues; it was found to be highest in the ear skin and lowest in the jejunum and stomach. After pretreatment with semicarbazide (plus a pyridoxine-free diet) or reserpine, or after adrenalectomy, the antihistamine activity was reduced in some tissues but was increased in others. The variation in the behavior of the different tissues with these treatments made it impossible to interpret the distribution of antihistamine activity in terms of known sites of amine formation. After treatment with compound 48/80, however, there was an apparent parallelism between loss of antihistamine activity and depletion of mast cell histamine.

Assay-guided isolation of naturally-occurring neuroactive substances

1985 ◽  
Vol 15 (1) ◽  
pp. 15-26 ◽  
Author(s):  
Henry McIlwain
Keyword(s):  
Growth Factors ◽  
Chemical Nature ◽  
Chemical Separation ◽  
Assay System ◽  
Neural Systems ◽  
Nerve Growth ◽  
Tissue Extracts ◽  
Naturally Occurring ◽  
Nerve Growth Factors ◽  
Chemical Techniques

SynopsisWays in which chemical techniques could be applied to the understanding of neural systems, their functioning and their disorders were devised only gradually during the present century. In a particularly successful procedure, now termed assay-guided isolation, neural defects were made good by means of tissue-extracts and the restoration of function was established as an assay-system to guide the chemical separation and identification of the active tissue constituent. Thiamin was so isolated, using an experimental polyneuritis assay; subsequent instances among other metabolites, hormones, neurotransmitters and nerve growth factors are recounted. Procedures of assay-guided characterization ensured that links were retained between specific, sparsely-occurring substances and chosen aspects of their biological roles while their chemical nature was first explored and then established. The procedures discouraged the too-facile postulating of hypothetical molecules and contributed to the distinctiveness of neurochemistry as a subject within the neurosciences.

scholarly journals The relationship between placental protein synthesis and transfer of amino acids

1983 ◽  
Vol 210 (1) ◽  
pp. 99-105 ◽  
Author(s):  
M J Carroll ◽  
M Young
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Guinea Pig ◽  
Specific Radioactivity ◽  
Protein Amino Acid ◽  
Naturally Occurring ◽  
Placental Protein ◽  
The Relationship ◽  
Radioactivity Measurements

The relationship between placental protein synthesis and transfer of amino acids from mother to foetus was studied in the guinea pig, by using [U-14C]-lysine, -leucine, -glycine, -aspartate and -alpha-aminoisobutyrate. The uptake of label by protein was 12-16% of total label transferred. Cycloheximide inhibited incorporation of all naturally occurring amino acids into protein by 81-96% and transfer by 62-75%; the concentration of label in the free pool was increased for each. These findings were confirmed when specific-radioactivity measurements were made with L-[U-14C]lysine. The transfer of the non-protein amino acid alpha-aminoisobutyrate was not significantly decreased by cycloheximide. A model, linking protein synthesis to the generation of a transfer pool of amino acids, is proposed whereby inhibition of protein synthesis decreases the amount of amino acid available for transfer.

scholarly journals THE LEUKOTOXIC ACTION OF STREPTOCOCCI

1957 ◽  
Vol 105 (5) ◽  
pp. 463-484 ◽  
Author(s):  
Armine T. Wilson
Keyword(s):  
Guinea Pig ◽  
Human Neutrophils ◽  
Polymorphonuclear Cells ◽  
Streptococcal Disease ◽  
Naturally Occurring ◽  
Cellular Debris ◽  
High Incidence ◽  
Group A ◽  
A Chain ◽  
Almost All

Following phagocytosis of certain streptococci human neutrophils undergo a rapid disintegration: the leukotoxic reaction. Monocytes and eosinophils are similarly injured, as are polymorphonuclear cells of rabbit and guinea pig blood. The leukotoxic injury is not produced by culture filtrates of leukotoxic cocci nor does it follow phagocytosis of heat-killed cocci. The leukotoxic effect does not appear to be due to action of any presently known streptococcal product. The distribution of leukotoxicity among streptococci is not random, for it was found in all strains tested of certain types of group A (6, 12), and was absent from almost all strains of other types (5, 14, 30). Still other types (3, 4) had both leukotoxic and non-leukotoxic representatives. The injury was also produced by some group C and G strains. Often the streptococci that cause leukocyte death remain alive and proliferate in the cellular debris, but sometimes they are injured by the phagocyte before the latter disintegrates and are unable to proliferate on the slides. The capacity of a strain of streptococcus to injure leukocytes does not necessarily confer virulence on it. This is thought to be because a chain of streptococci, having survived its sojourn in a leukocyte it has killed, is still susceptible to phagocytosis by a fresh leukocyte, and serial phagocytoses may continue until the chain has been exposed sufficiently to the unfavorable intracellular environment to be, itself, killed. Whether leukotoxicity plays a role in naturally occurring streptococcal disease is unknown. The high incidence of leukotoxicity in Type 12 strains suggested that it might be involved in acute hemorrhagic nephritis, but if so there must be other factors since leukotoxic strains are present in types and groups not now known to be associated with nephritis.

The Conformations of Virginiamycin M1 Diacetate, an Inhibitor of Guinea Pig Brain CCK-B Receptors, in Selected Solvents

2020 ◽  
Vol 73 (3) ◽  
pp. 230
Author(s):  
Kevin Walsworth ◽  
Anastasiya Bender ◽  
Frances Separovic ◽  
B. Mikael Bergdahl ◽  
Robert P. Metzger
Keyword(s):  
Guinea Pig ◽  
Binding Site ◽  
Receptor Binding ◽  
Parent Compound ◽  
Cyclic Structure ◽  
Peptide Receptor ◽  
Naturally Occurring ◽  
Pig Brain ◽  
Virginiamycin M1 ◽  
Guinea Pig Brain

The Virginiamycin M1 derivative Virginiamycin-14,16-diacetate (VM1-diAc) is not naturally occurring and must be synthesised by those wishing to study its properties. It possesses very little if any of the antibiotic capabilities of its parent compound, Virginiamycin M1. However, VM1-diAc has been reported to bind competitively to guinea pig brain cholecystokinin (CCK-B) receptors at concentrations very near that of CCK-B itself. CCK-B may bind to the CCK-B receptor as an octa- or a tetrapeptide, suggesting that a portion of the VM1-diAc molecule has a conformation very similar to the binding site of the CCKB peptide. Since the conformations of the VM1-diAc are constrained by its cyclic structure, studies of its binding to the CCK-B receptor might provide useful information about the CCK-B peptide receptor binding. To begin such a project, we report herein results of a study of the conformations of VM1-diAc dissolved in chloroform and methanol, two solvents of different polarities.

HEPARINASE: III. PREPARATION AND PROPERTIES OF THE ENZYME

1956 ◽  
Vol 34 (4) ◽  
pp. 799-813 ◽  
Author(s):  
M. H. Cho ◽  
L. B. Jaques
Keyword(s):  
Enzyme Activity ◽  
Guinea Pig ◽  
Ammonium Sulphate ◽  
Enzyme Concentration ◽  
Optimal Conditions ◽  
Isoelectric Precipitation ◽  
Tissue Extracts ◽  
Optimum Ph ◽  
Liver Homogenates ◽  
Dog Liver

The extraction of heparinase from beef and rabbit liver has been studied. Optimal conditions for precipitation of the enzyme were 33% ammonium sulphate, pH 7.0; 7% ethanol, pH 5.0–5.5; 40–70% acetone, pH 8.0; with 0.1% NaCl for ethanol and acetone. A new method of preparation of the enzyme is described, using extraction with 0.15 M KCl, precipitation with 33% ammonium sulphate, isoelectric precipitation at 6.0, elution at 37 °C, and precipitation at 5.0. This preparation gave a 50% destruction of heparin in three hours. The optimum pH was 4.8, substrate concentration, 0.2 mgm./ml. Higher concentrations inhibited the enzyme. A linear relation was not obtained between enzyme concentration and velocity of the reaction. The enzyme was inhibited by mercuric chloride, magnesium chloride, lithium chloride, iodoacetate, glutathione, methionine, versene, and citrate. In liver homogenates, the enzyme activity was associated with all fractions (microsomes, mitochondria, etc.). Active preparations were obtained from liver of man, ox, pig, rabbit, guinea pig, rat, gopher; kidney of ox, pig, rabbit, guinea pig, and rat; muscle of rabbit and guinea pig. No activity was obtained from dog liver, ox testis and thymus, human placenta. Difficulties in assaying heparinase in tissue extracts are discussed.

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