DIFFERENCES IN THE CLOTTING OF LAMPREY FIBRINOGEN BY LAMPREY AND BOVINE THROMBINS

1. Improved methods for the purification of lamprey thrombin and fibrinogen are presented. 2. Lamprey thrombin releases two fibrinopeptides from lamprey fibrinogen during the transformation into fibrin. Bovine thrombin releases only one of these, a peptide referred to as fibrinopeptide B. The differences in the by-products of fibrin formation are reflected in the different N-terminal amino acid compositions of the two types of fibrin. 3. The fibrinopeptide that is not removed from the lamprey fibrinogen by bovine thrombin can subsequently be released by treatment of that fibrin with lamprey thrombin. 4. Under the conditions used, lamprey thrombin releases both fibrinopeptides at about the same rate. 5. The differences in interaction among these pairs of related proteins are extreme manifestations of the phenomenon loosely referred to as ;species specificity'.

INTRASPECIFIC AND INTERSPECIFIC TRANSFORMATION IN STREPTOCOCCI

Perry, Dennis (Northwestern University Medical School, Chicago, Ill.), and Hutton D. Slade. Intraspecific and interspecific transformation in streptococci. J. Bacteriol. 88:595-601. 1964.-Interspecific transformation reactions, employing streptomycin resistance as a marker, were performed with eight strains of streptococci belonging to three serological groups (F, H, and O) and one ungroupable (UG) strain. Generally, autotransformation (within the same strain) was most efficient. Homotransformation (between different strains of the same serological group), however, was sometimes as efficient or slightly better. Heterotransformation (between different serological groups) yielded the least number of transformants or none at all. The rate of transformation of different strains varied from 2.0 x 10(-7) to 7.6 x 10(-3). Group H streptococci exhibited the highest rate of autotransformation, followed by groups F and O, and strain UG. The results of heterotransformation reactions revealed that a genetic relationship exists between various strains of different serological groups. No transformation, however, occurred between F and O strains, indicating a lack of genetic homology between these serological groups of streptococci. Deoxyribonucleic acid (DNA), isolated by physical and enzymatic methods from a group O and a UG strain, failed to induce transformation. DNA from these strains, however, significantly inhibited the transforming ability of other DNA preparations. Heat and mechanical shear resulted in a marked decrease in this inhibitory property.

IMMUNO-ELECTRON MICROSCOPE ANALYSIS OF THE SURFACE LAYERS OF THE UNFERTILISED SEA URCHIN EGG. I. EFFECTS OF THE ANTISERA ON THE CELL ULTRASTRUCTURE

The response of unfertilised Paracentrotus lividus eggs to γ-globulin fractions of antisera against isolated homologous jelly coat substance or homologous homogenates of jellyless eggs has been studied at the ultrastructural level. The antijelly γ-globulin caused precipitation of the jelly layer, the density of precipitation varying between different eggs and being proportional to the γ-globulin concentration. Agglutination of the jelly substance of adjacent eggs, which is species specific, occurred frequently with higher γ-globulin concentrations. Antiegg γ-globulins (from antiserum against total homogenates of jelly-free eggs or the heat-stable fraction thereof) did not produce these effects. Instead, these γ-globulins caused various structural alterations mostly representing stages in parthenogenetic activation. This species-specific activation was induced by the reaction of antibodies with some heat-stable egg antigens different from those involved in jelly precipitation. Surface alterations included the formation of small papillae, membrane blisters, hyaline layer, and activation membrane, the release of material from the cell surface, and the breakdown of cortical granules. These alterations were dependent on both γ-globulin concentration and the variable reactivity among different females. Aster formation, found intracellularly, verified that the surface responses represented real parthenogenetic activation and were not the result of immune lysis. No such alterations appeared in the controls.

THE METABOLISM OF PROGESTERONE BY ANIMAL TISSUES IN VITRO. SEX AND SPECIES DIFFERENCES IN CONJUGATE FORMATION DURING THE METABOLISM OF (4-14C)PROGESTERONE BY LIVER HOMOGENATES

1. Sex and species differences during the metabolism of [4-(14)C]progesterone by liver homogenates from rat, rabbit, guinea pig and hamster have been investigated. 2. Liver homogenate from male rat formed ;water-soluble' metabolites faster and in significantly larger amounts than did liver homogenate from female rat. About 65-70% of the added progesterone was conjugated as glucuronide by liver homogenate from male rat and about 45-50% by that from female rat. Liver homogenate from male rat also formed glucuronides faster than did liver homogenate from female rat. Sulphate formation was low (8-16%) in liver homogenates from both male and female rats. 3. Hamster-liver homogenate did not show any sex difference in the rate of formation of ;water-soluble' metabolites, but a sex difference was observed in the amount of free steroids recovered at low tissue:steroid ratios. Liver homogenate from female hamster formed glucuronides faster and in significantly larger amounts than did liver homogenate from male hamster, the reverse of what was found in rat liver. 4. Liver homogenates from male and female rabbits and guinea pigs formed ;water-soluble' metabolites that were almost entirely glucuronides. 5. Neither rabbit liver nor guinea-pig liver showed any significant sex difference in the rate or amount of formation of total ;water-soluble' metabolites or glucuronides, but guinea-pig liver was considerably less active than rabbit liver. 6. Glucuronides were quantitatively the major type of conjugate formed by the liver homogenates from both sexes of all species except the male hamster.

EXPERIMENTAL GLOMERULONEPHRITIS. IV. PARTICIPATION OF COMPLEMENT IN NEPHROTOXIC NEPHRITIS

Rats with nephrotoxic serum nephritis may show fixation of complement (C') in the glomeruli during two periods. The first period occurs immediately after the injection of the antisera and extends until the host response occurs. The second period is related to the deposit of rat gamma globulin in the glomeruli presumably occurring at the time of the immune response to the heterologous nephrotoxic serum (NTS). This second period terminates about 2 to 3 weeks after injection of NTS, presumably at the time the rat stops making antibodies to the nephrotoxic gamma globulin fixed in the glomeruli. After this period, the glomerular lesion is incapable of fixing detectable amounts of circulating C' unless the antibody response to the heterologous globulin is reactivated. The immunological events which take place in the initial 2 to 3 week period appear to produce a permanent and irreparable lesion in the glomeruli leading to chronic nephritis. Rabbit NTS produces fixation of rat C' during both periods. Duck NTS shows no detectable fixation of rat C' until rat gamma globulin fixes in the glomeruli at the time of the host immune response to the heterologous nephrotoxic gamma globulin. Decomplementation of rats injected with rabbit NTS produces an amelioration of the initial period of nephrotoxic serum nephritis. The fixation of C' in the glomerular lesions was studied with the use of fluorescent antibody methods. The detection of host beta-1C globulin and gamma globulin in the glomerulus pointed to an immune reaction but not necessarily an active one. The tissue C' fixation test using kidney slices and guinea pig C' proved to be a more sensitive method of detecting tissue reactants capable of fixing C', but its relationship to in vivo events is not certain.

A TERATOGENIC EFFECT OF A SULPHONAMIDE IN EXPERIMENTAL ANIMALS

Sulphamoprine, when given in the diet at levels from 0.025% upwards to pregnant rats and mice, produced abnormalities of eruption of the incisor teeth and of the skull of the offspring. Rabbits are not susceptible to this teratogenic action.

SEROLOGICAL STUDIES ON GROUP- AND SPECIES-SPECIFIC ANTIGENS OF TRACHOMA AND INCLUSION CONJUNCTIVITIS (TRIC) AGENTS

Group-reactive ether soluble psittacosis and boiled mouse pneumonitis antigens were tested in parallel, with 85 serum specimens. The results indicate that the group-specific C.F. antigens of these organisms are indistinguishable when tested against sera of trachoma patients, monkeys infected with trachoma or against sera of other individuals.

Sera of rabbits immunized with viable trachoma-inclusion conjunctivitis (TRIC) organisms, grown in tissue culture, were absorbed with boiled elementary body suspension of mouse pneumonitis agent, which removed the group reactive antibodies, and resulted in a species-specific anti-TRIC serum.

The absorbed and unabsorbed TRIC sera were titrated against purified E.B. suspensions, which were prepared both from yolk and from tissue culture grown organisms, of homologous TRIC strains and from other heterologous Bedsonia organisms.

Results of absorption experiments indicate that group reactive antigens prepared from mouse pneumonitis and psittacosis are indistinguishable by C.F. test from the group-specific component of the TRIC antigens. The species-specific antigen of the TRIC agents was well distinguished from the species-specific antigen of the psittacosis agent. However, the C.F. test did not distinguish the strains isolated from trachoma from those isolated from cases of inclusion conjunctivitis.

The stabilizing effect of sucrose and albumin upon the species-specific C.F. antigen of purified elementary bodies of TRIC organisms was found to be pronounced.

Our attempts to produce a species-specific antigen preparation, free from group component, failed.

We have pleasure in thanking Dr F. B. Gordon for suggestions; Dr B. V. Birtašević, Mr H. R. Dressler, Dr E. S. Murray and Dr A. J. Vargosko for procuring sera of patients or organisms grown in tissue culture; Dr T. A. Strike for the help with statistical computations; HMC P. R. Hill, HM3 C.O. Wiese and Mr B. L. Ward for invaluable technical assistance.

EVIDENCE FOR SPECIES' DIFFERENCES IN THE EFFECT OF SERUM GAMMA-GLOBULIN CONCENTRATION ON GAMMA-GLOBULIN CATABOLISM

The fractional rates of catabolism of isotopically labeled mouse, human, bovine, and guinea pig gamma-globulins and human serum albumin were determined in mice and in guinea pigs whose serum gamma-globulin and serum albumin levels were elevated by immunization or by injections of exogenous serum proteins. These serum proteins were also followed in mice with different serum gamma-globulin levels due to different bacterial environments. The fractional rates of catabolism of the labeled gamma-globulins from all species tested were markedly increased in mice with elevated gamma-globulins due to immunization; to injections of human, mouse, guinea pig, or rabbit gamma-globulins; to exposure to supra normal numbers of bacteria in the environment. Injections of bovine gamma-globulin were only partially effective, and injections of human serum albumin had no effect. The gamma-globulin catabolic rates were decreased in mice with subnormal serum gamma-globulin levels (germfree mice). The catabolic rate of human serum albumin was essentially the same in all mice in spite of differences in serum gamma-globulin levels. In contrast, elevation of the serum gamma-globulin levels by injections of exogenous gamma-globulins or by hyperimmunization with keyhole limpet hemocyanin produced no change in the fractional catabolic rates of the isotopically labeled gamma-globulins and labeled albumin in guinea pigs. Thus, a feedback mechanism for the control of the serum gamma-globulin concentration appears to be operative in the mouse, but not in the guinea pig. Guinea pigs immunized with antigens in complete Freund's adjuvant or a saline suspension of killed E. coli had an increase in the catabolic rates of all labeled proteins tested including human serum albumin. Evidence is presented that the mechanism of this increase in catabolism is not the same as that seen in mice with elevated serum gamma-globulin levels.

A STUDY OF RABBIT GAMMA-GLOBULIN ALLOTYPY BY MEANS OF HETEROIMMUNIZATIONS

Representatives of two species, the chicken and the goat, were immunized by injection with Freund's adjuvant, of specific precipitates prepared from the antisera of rabbits with various allotypic specificities. The precipitation reactions of the resulting antisera with normal rabbit sera were studied in liquid and in gellified media. In these reactions the isotypic specificity and often one or the other of the allotypic specificities of rabbit gamma-globulin were involved. It was always easier to obtain antibodies against the specificities controlled by the alleles of locus b (Ab4, Ab5, Ab6) than of locus a (Aa1, Aa2, Aa3). The precipitation reaction of antibodies against a specificity of the a series could always be inhibited by an excess (nearly always moderate) of a serum lacking this specificity. A similar inhibition of the antibodies against the specificities of the b series was often impossible, especially if the antiserum had been collected after a second injection of immunizing material. The reactions of 58 Ab4(+) sera with a goat anti-Ab4 serum and of 28 Ab5(+) sera with a chicken anti-AbS serum were studied in gel tubes (simple diffusion). The constant observation of two precipitation zones due respectively to two types of molecules, Ab4(+) and Ab4(-) (or Ab5(+) and Ab5(-)), indicated the existence of an appreciable number of Ab4(-) or Ab5(-) molecules, even in supposed homozygotes. In the latter rabbits Ab4(-) or Ab5(-) molecules are b(-) molecules; i.e., molecules lacking the specificities of the b series. Measurements of the distances between the two zones in the reaction of 72 sera revealed significant differences between sera of individuals of the same phenotype, as well as systematic differences not only between sera of homozygotes and of heterozygotes, but also between heterozygotes of different genotypes. These measurements were used to evaluate the ratio of concentrations of the two types of molecules detected by each of the two antisera. The occurrence of b(-) molecules in every one of the fairly large number of sera studied indicates a new aspect of the heterogeneity of gamma-globulin. Although detected by means of allotypy, this heterogeneity is not dependent upon factors which vary with individuals. These results are discussed in connection with what is known of the structure of gamma-globulin.

COMPARATIVE STUDIES OF FRANCISELLA TULARENSIS AND FRANCISELLA NOVICIDA

Owen, C. R. (U.S. Public Health Service, Rocky Mountain Laboratory, Hamilton, Mont.), E. O. Buker, W. L. Jellison, D. B. Lackman, and J. F. Bell. Comparative studies of Francisella tularensis and Francisella novicida. J. Bacteriol. 87:676-683. 1964.-Comparative studies of various properties of Francisella tularensis (= Pasteurella tularensis) and F. novicida were performed. The two organisms are very similar morphologically. Growth of both was markedly enhanced by addition of cystine to media, but F. novicida is less fastidious than F. tularensis. The virulence of F. novicida for mice and cavies is lower than that of fresh isolates of F. tularensis. In complement-fixation tests, some cross-reaction occurred when rabbit antisera were used; complement-fixation tests with cavy antisera were specific. Agglutination tests with sera from both rabbits and cavies were specific. Nonliving vaccines of the two organisms (extracts, whole dead cells) conferred no cross-protection to mice; living attenuated vaccines conferred cross-protection which was more transitory than was specific protection. Passive cutaneous anaphylaxis (PCA) tests were highly specific. Absorption of antisera with homologous organisms removed all PCA reactivity, while absorption with heterologous organisms left it almost intact. Hemagglutination and hemagglutination-inhibition tests were specific. It was concluded that the two organisms are sufficiently similar to belong in the same genus but sufficiently different to be retained in separate species.

INDIRECT FLUORESCENT ANTIBODY TECHNIQUE IN THE SEROLOGY OF TOXOPLASMA GONDII

The indirect fluorescent antibody technique has been used to titrate patients' antibody against Toxoplasma gondii. Rigorous tests of the immunological validity of the method were made. The reactions of the gamma globulin of human immune serum with Toxoplasma gondii and fluorescent rabbit anti-human gamma globulin were thus shown to be specific. Thereafter the technique could be used with confidence to detect the reaction between doubling dilutions of patient's serum and smears of unfixed Toxoplasma gondii. In this way, titres were obtained with the indirect fluorescent antibody technique which agreed well with those of the dye test at both low and high levels of antibody. Compared with the dye test, the indirect fluorescent antibody technique has many advantages. The end-point is sharp and obviates the counting of stained and unstained organisms; supplies of antibody-free accessory factor sera are not needed; prozones undetected by the dye test are strongly positive at screening dilutions, the reagents keep indefinitely and lend themselves to preparation, standardization, and issue by a central reference laboratory.

PHYSIOCHEMICAL AND BIOLOGICAL PROPERTIES OF GLYCOPROTEINS ISOLATED FROM THE PLASMA OF DIFFERENT SPECIES OF ANIMALS

1. Glycoproteins were isolated from the plasma of sheep, goat, cow, buffalo and monkey. They were homogeneous by electrophoresis; on ultracentrifugation, a faster-sedimenting fraction, to an extent of 5-8% only, was observed in each case. 2. Similar physical properties were exhibited by these glycoproteins and they each have a molecular weight of about 105000. 3. In chemical composition, differences have been observed and the glycoproteins can be classified into three groups: (a) sheep and goat glycoproteins; (b) cow and buffalo glycoproteins; (c) monkey glycoprotein. Glucose, galactosamine and N-terminal amino acid were absent from these proteins. 4. These glycoproteins were trypsin inhibitors and prolonged the clotting time of plasma.

THE REGULATION OF UREA-BIOSYNTHESIS ENZYMES IN VERTEBRATES

1. Carbamoyl phosphate synthetase, ornithine transcarbamoylase, the arginine-synthetase system and arginase were measured in the livers of ammoniotelic, ureotelic and uricotelic animals. The chelonian reptiles, whose nitrogen excretory patterns vary according to the habitat, and the Mexican axolotl, a neotenic species, were also studied. 2. The levels of the activities of the first three enzymes mentioned correlate with the amount of nitrogen excreted as urea. 3. The terrestrial turtle, which excretes mainly uric acid, maintains a high arginase activity but has very low levels of the activities of the other three enzymes. 4. The first three enzymes of the urea cycle vary in the phylogenic scale in a co-ordinated manner, which suggests that they are under the same regulatory mechanism. 5. Urea formation from endogenous arginine in vitro has a low efficiency in the Mexican axolotl. 6. The induction of metamorphosis in the Mexican axolotl by the administration of l-tri-iodothyronine, which causes a shift from ammonio-ureotelism to complete ureotelism, is accompanied by an increase mainly in carbamoyl phosphate synthetase and also by an improvement in the efficiency of hydrolysis of endogenous arginine in vitro to give urea. 7. The results obtained by differential centrifugation of the urea-cycle enzymes in rat and Mexican-axolotl livers are presented. The location requirements for the integration of a metabolic cycle are discussed.