Comparative biochemistry and physiology最新文献

1. By use of specific synthetic substrates and inhibitors, trypsin and chymotrypsin have been demonstrated in the digestive tracts of both sexes of adult Carabus taedatus and Calosoma calidum.

2. No evidence for carboxypeptidase-A, carboxypeptides-B or aminopeptidase was found.

3. At 30°C the trypsin has a pH optimum at pH 8·2–8·3.

4. The trypsin has been partially purified and its molecular weight estimated by Sephadex G-100 column chromatography to be approximately 20,000–23,000.

5. The trypsin is inhibited by TLCK, PMSF, 2-mercapto-ethanol, human and porcine serum.

1. Electrophoretic patterns of proteins and acid mucopolysaccharides found in cell-free coelomic fluid and extracts of ceolomic cells of Strongylocentrotus franciscanus, S. purpuratus, and Centrostephanus coronatus differed according to the urchin species. Most of the proteins were PAS-positive.

2. In cell-free coelomic fluid, echinochrome A (6-ethyl-2,3,7-trihydroxynaphthazarin) is bound to one or more PAS-positive proteins, according to the urchin species. The same proteins occur in echinochrome-free fluids. In cell extracts echinochrome occurs in PAS-positive proteins that also have an acid-mucopolysaccharide moiety.

3. Purified echinochrome A conjugated with the proteins ovomucoid and calf-thymus histone, and with macromolecules in fresh cell-free sea-urchin coelomic fluid. It did not conjugate with bovine gamma globulin, or with molecules in concentrated coelomic fluid.

1. Carnosine and anserine activate rabbit skeletal muscle myofibrillar-ATPase activity.

2. The total carnosine plus anserine found varies from species to species but is of the order of 20 μmoles per gram of tissue or greater.

3. Invertebrate muscle, however, contains little or no carnosine or anserine.

4. The effects of carnosine on the ATPase activity of myofibrils from rabbit and chicken skeletal muscle and from the muscle of eartworm, lobster and clam were compared.

5. Carnosine had no activiating effect on the ATPase activity of the invertebrate systems in contrast to a two-fold activation of rabbit and chicken skeletal muscle myofibrillar-ATPase activity.

6. The results indicate that carnosine activiation of myofibrillar-ATPase activity may be limited to myorfibrils from muscles that normally contain carnosine and/or anserine as major constituents.

1. Changes in cytochrome oxidase activities following prolonged oxygen depletion induced by a maintained underwater “drive” were investigated in the pond turtle (Pseudemys scripta elegans).

2. A marked decrease in both heart and skeletal muscle cytochrome oxidase activity was seen following 48 hr of total anaerobiosis. Heart: Control = 4·05 ± 0·86; diving = 3·07 ± 0·74; P = < 0·05. Skeletal muscle: Control = 0·90 ± 0·24; diving = 0·44 ± 0·13; P < 0·01.

3. This decrease may be a consequence of a need for molecualr oxygen in porphyrin biosynthesis, may subserve increased metabolic efficiency, or may be a reflection of the lowered (zero) mitochondrial oxgyen consumption.

1. The kynurenine transaminase of different tissues and of the haemolymph of adult Schistocerca gregaria was studied. It is present only in the homogenate of the locust fat body.

2. It is active both on kynurenine and 30H-kynurenine. The K_m is 4·4 × 10⁻⁴ M for kynurenine and 1·5 × 10⁻³ M for 30H-kynurenine. For both substrates the optinum pH is 8.

3. Pyruvic and oxalacetic acids are slightly more active than α-ketoglutaric acid as—NH₂ acceptors. High concentrations of ketoacids are not inhibitory. Pyridoxal phosphate is necessary for the enzyme acitivity.

4. Locust kynurenine transaminase is similar to the same enzyme of mammals; one of the differences is that for the locust enzyme the best—NH₂ acceptor is pyruvic acid.

1. The effects of age and strain of the domestic fowl (Gallus gallus) on the lipid content and composition of the exterior structures of the egg were studied.

2. The inner shell membrane contained the greatest amount of lipid material followed by the outer shell membrane and the shell with cuticle.

3. The major portion of the total lipids was neutral lipid which was found to contain mono-, di- and triglycerides, as well as cholesterol, cholesterol esters and free fatty acids.

4. The phospholipid portion of the total lipid contained lysolecithin, lecithin, cephalin, and sphingomyelin.

1. Liver arginase (E.C. 3.5.3.1) of various mammalian species (rat, mouse, dog, rabbit, pork, monkey) were partly purified and their isoelectric properties determined by carboxymethyl cellulose column chromatorgraphy and isoelectric focusing.

2. The ureotelic arginase can be divided into mainly two groups; (i) basic and (ii) slightly acidic or neutral proteins.

3. The two groups of arginases showed marked differences in the binding of Mn²⁺.

4. Only beef liver arginase could be activated by Co²⁺ and Ni²⁺, all other mammalian arginases were inhibited by these metal ions.

5. The molecular weights were found to range from 120,000–160,000 daltons.

6. High Michaelis constanta (6–20 mM) were obtained for all arginases studied.

7. Similarities were also found in the pH optima (pH 9·3–10·5) as well as the optimal Mn²⁺ concentration (40 mM) required to obtain maximal catalytic activity.

1. Extracts from each of the fat body, thoracic and appendage muscle of both sexes of the American cockroach yielded a single disc electrophoretic GDH fraction, which was quantitative and qualitatively stable during the first 6 months of the imago.

2. Enzymes extracts from 3 cockroach species were heat stable at 52° for 30 min.

3. GDH patterns were highly species-specific among the 24 cockroach species analyzed. Generic relationships were postulated on the basis of R_f similarity.

4. Clones of parthogenetic Pycnoscelus surinamensis, with modal chromosome complements of 34 to 54, each had a single GDH fraction and all R_f values were identical.

The study of blood serum proteins by different electrophoretic techniques provides a way to study speciation characters among dolphins.

2. The electrophoretic analysis has allowed at least twenty-one constituents to be numbered in Delphinus delphis; twelve of these have been antigenically defined with an anti-D. delphis antiserum. The electrophoretic and immunoelectrophoretic analyses of serum proteins in the species Stenella styx have shown that the two species are almost identical at the serum protein level.

3. Only sixteen constituents are numbered in the serum of Grampus griseus, twelve of whic have been antigenically defined with anti-D. delphis and anti-S. styx antiserums and are common to the three species.

4. Seventeen constituents are numbered in the serum of Globicephala melaena. After the antiserums anti-D. delphis and anti-S. styx have been drained by G. melaena serum, they still posses one antibody which reacts with a β-1-globulin present in D. delphis, S. styx and G. griseus serums. This β-1-globulin appears to be lacking in G. melaena serum.

5. Other differences have been shown between the group formed by D. delphis and S. stys and the two other species, particularly at the transferrin level.

6. The existence of a group system of transferrins has been shown among D. delphis and S. stys.

1. Acetate-¹⁴C incorporation by the homogenates of the eggs, larvae, pupae and adults of Ceratitis capitata shows clear differences. The pupal and larvae stages of development exhibit the most effective incorporation.

2. NADPH influences the acetate incorporation in a different way. It enhances the incorporation by larval homogenate whereas it produces a net decrease of the incorporation by pupa homogenate.

3. Citrate decreases the acetate incorporation by all homogenates. This effect is higher in the pupal homogenate. As for the influence of citrate on the activatory effect of the mixture ATP-Mg²⁺ in larval and pupal homogenates, incorporation by larval and pupal homogenates is enhanced and decreased respectively.

4. Differences in the regulation of fatty acid synthesis during larval and pupal stages of development are clearly shown.