Developmental genetics of teleosts: a biochemical analysis of lake chubsucker ontogeny

Developing embryos of the lake chubsucker, Erimyzon sucetta, were analyzed with regard to both gross morphological changes and specific enzymatic changes from the unfertilized egg stage until some 3 weeks posthatching. Total activities of three enzymes—lactate dehydrogenase, glucose-6-phosphate dehydrogenase, and isocitrate dehydrogenase—were determined throughout the course of development. Each of these different enzymes exhibited a different pattern of change during ontogeny. Electrophoretic analysis of qualitative changes in isozyme patterns was accomplished for these three enzymes and for α-amylase, glucosephosphate isomerase, mannosephosphate isomerase, creatine kinase, esterase, glutamate dehydrogenase, alkaline phosphatase, aspartate aminotransferase, malate dehydrogenase, hexose diphosphatase, phosphoglucomutase, and phosphogluconate dehydrogenase. Many of the enzyme systems investigated exhibited rich patterns of ontogenetic change, while a few remained relatively unchanged throughout the interval studied. Several of the enzymes in particular metabolic pathways exhibited coincident changes suggestive of coordinate control. The appearance of several rather “tissue-specific” isozymes was closely correlated with the morphological and functional differentiation of these particular tissues or organs.     

The role of progesterone in pregnancy-induced aggression in mice

A series of six experiments was performed in order to explore the potential involvement of progesterone (P) in pregnancy-induced aggression (PIA) displayed by Rockland-Swiss mice toward adult male intruders. In Experiment 1, circulating levels of P and aggression were low on gestation Days 6 and 10 while both the behavior and the steroid reached peak levels by gestation Day 14. By gestation Day 18 (the day prior to parturition), serum P was at its lowest level yet aggressive behavior was still intense. Also, individual differences in the display of fighting behavior by pregnant females were not related to circulating P. Experiments 2 and 3 showed that supplemental P treatment to early pregnant female mice did not advance the onset of aggression. Experiment 4 showed that P treatment promoted the onset and elevated the incidence of aggression in virgin mice, but only in those females with intact ovaries. Experiment 5 showed that the aggressive behavior of P-stimulated virgin females was qualitatively and quantitatively different from that exhibited by pregnant mice in that the former exhibited fewer attacks and lunges than the latter. Finally, Experiment 6 showed that the removal of P from aggressive, P-stimulated virgins dramatically attenuated levels of the behavior. This contrasts sharply with the continued fighting behavior observed in late pregnant P-deficient mice. Thus, although P augments aggression in female mice it apparently is not a sufficient stimulus for producing pregnancy-like aggressive behavior.     

Analysis of double-helix motions with spin-labeled probes: binding geometry and the limit of torsional elasticity

The e.p.r.⁵ spectra of a family of spin-labeled probes non-covalently bound to DNA have been measured as functions of helix orientation, packing density and temperature. The spectra are interpreted in terms of the geometrical relations between the helix axis and the orbital containing the unpaired electron and in terms of the motions of the helix. Torsional and flexural motions can be distinguished.Spectra from well-ordered helices have been obtained using fully hydrated DNA fibers that are in thermodynamic equilibrium with unbound probe in dilute salt solution. The binding equilibria are similar to the equilibria in dilute DNA solution. The spatial relations between the spin label and the helix, inferred from the spectra, correspond closely to the structure expected on the basis of intercalation perpendicular to the helix axis and a sterically hindered amide bond between the spin label and the intercalating moiety of the probe. Viscometric measurements with one probe also indicate intercalation.Linear e.p.r. spectra of solutions, randomly condensed DNA, and fibers show substantial torsional motion but no detectable flexure on the linear e.p.r. time scale (> 300 ns). The correlation time of a propidium-based probe is much longer than that of aminoacridine intercalators. The probes with short correlation times are considered to be too weakly coupled to the adjacent base-pairs to be reliable indicators of DNA dynamics. For the propidium probe the correlation time, 30 nanoseconds, and its temperature dependence are compared with the properties expected according to four models: tight rotational coupling along the entire length of the helix; swivels at fixed intervals; a two-state exchange; and elastic rotational coupling between adjacent nucleotide pairs. In terms of the fourth model, the results suggest that each nucleotide pair undergoes random oscillation with an r.m.s. amplitude of not more than 4 ° to 5 ° at room temperature. That value agrees with estimates made in other ways.     

Properties of the genome in experimental hepatomas: variations in the composition of chromatin

The chromosomal proteins of two rapidly growing and poorly differentiated Morris hepatomas were compared with those of liver from normal and tumor bearing animals. While the total quantity of histone associated with DNA in all tumor and liver chromatin preparations studied were similar, tumor chromatin contained an increased quantity of nonhistone chromosomal proteins. Variations in specific classes of histones and nonhistone chromosomal proteins associated with the genome of the two tumors, host liver and liver of tumor bearing animals were observed.     

Steroidal influences on pup-killing behavior in mice

Four experiments were conducted in order to examine the biochemical pathway through which testosterone (T) acts to produce pup-killing behavior in ovariectomized female mice. Estradiol benzoate (EB) and testosterone propionate (TP) were both effective in stimulating the pup-killing response (Experiment 1). The nonaromatizable androgen dihydrotestosterone (DHT) and the aromatizable androgen testosterone (T) were equipotent in eliciting the behavior while the nonaromatizable androgen androstanedione (AA) was ineffective (Experiment 2). Pup-killing behavior was activated by the aromatizable androgen androstenedione (AE) but only if it was administered chronically at very high doses (Experiment 3). The combination of subthreshold doses of EB and DHT synergized to produce the pup-killing response (Experiment 4). These findings suggest that both aromatization and reduction may be important for the stimulation of pup-killing behavior in mice.     

Ergot drugs suppress plasma prolactin and lactation but not aggression in parturient mice

The daily administration of pituitary prolactin (PRL) inhibitors (ergocornine hydrogen maleate and 2-bromo-α-ergocryptine) to parturient Rockland-Swiss Albino mice suppressed circulating levels of PRL and lactation but failed to alter maternal aggression toward adult male intruders. The results suggest that, contrary to popular speculation, PRL may not be necessary for postpartum aggression in the mouse.     

X-ray-induced mutations affecting the level of the enzyme alcohol dehydrogenase in Drosophila melanogaster: frequency and genetic analysis of null-enzyme mutants.

The frequency of X-ray-induced (null-enzyme) mutations at the alcohol dehydrogenase locus in Drosophila melanogaster was measured. The rate of recovery of chromosomes that fail to direct the synthesis of a functional Adh protein is 3 x 10(-8) per R for chromosomes that do not include large chromosome rearrangements. However, this analysis excludes a larger number of chromosomes that are "null-enzyme mutations" because thye are deleted for the region of the Adh locus. The dose of X-rays required to induce a frequency of non-deletion null-enzyme mutants equal to the spontaneous frequency is about 73 rad calculated from the data reported in this communication.     

Limb outgrowth in the chick embryo induced by dissociated and reaggregated cells of the apical ectodermal ridge.

Mesodermal cores of the stage 19 chick leg bud were capped with an intact apical ectodermal ridge (AER) or with strips cut from centrifugal pellets formed from Pronase-dissociated AERs. They were then covered with embryonic back-skin ectoderm and grown as grafts to the somite region of a host embryo. Control mesoderms were capped with centrifugal aggregates of nonridge limb ectoderm or similarly treated back-skin ectoderm, with ethanol-killed AERs or with no ectodermal cells other than the enveloping back-skin ectoderm.Controls were vascularized slowly and atypically and showed little outgrowth, forming only proximal skeletal structures. Recombinants equipped with AER cells were vascularized more fully and promptly and began vigorous growth after brief delay, forming legs with all skeletal segments represented, including claw-tipped toes. The latter were arranged in anteroposterior order corresponding to the original polarity of the mesoderm.Histological sections of recombinants made with cytologically distinctive quail AERs reveal that the cap of ridge cells, whether initially intact or reaggregated beneath the back-skin envelope, undergo a period of reorganization, forming a typical AER at the apex of the chimeric appendage after 48 hr. Meanwhile vigorous growth of the recombinant continues.These results show that the AER can cooperate with nonlimb ectoderm in promoting the morphogenesis of successively more distal levels of the limb skeleton. They also show that dissociated ridge cells can reorganize a typical AER at the apex of the limb mesoblast, meanwhile exercising their inductive effect on it.     

A cross-species analysis of carnivore,primate, and hominid behaviour

The traditional assumption that the origin of human behavior is found within the higher primates rather than the social carnivores is based on failure to adequately define primate and carnivore behavior. Phyletic classification takes no account of convergence and divergence; the behavior of a species is not necessarily characteristic of its order. Of 8 behavior variables that distinguish the order primates from the order carnivora, preagricultural man resembles the carnivores on 7 items: food sharing, food storing, cannibalism, surplus killing, interspecies intolerance, feeding of young, and division of labor; resembling the order primates only in group defense. The original form of much human behavior is found within the carnivores.     

The mechanism of regulation of fibroblastic cell replication. III. A central role for nutrient limitation: a conditioning effect due to serum imprinting of the cell response

Haploid Saccharomyces cerevisiae cells of mating type a, but not α, produce and secrete a diffusible substance, designated a factor. The a factor transiently arrests cells of mating type α, but not a, at a very early stage of the cell cycle, prior to budding and to the initiation of DNA synthesis. While the cells are arrested at this stage, few, if any, of the functions required for the ensuing cell cycle are carried out. This stage of the cell cycle coincides with the stage at which α factor, produced by cells of mating type a, specifically arrests cells of mating type a [2]. It seems probable that the reciprocally acting a and α factors together provide the mechanism by which haploid cells are synchronized to the appropriate stage of the cell cycle as a prelude to conjugation.     

Double labeling of chromatin proteins,in vivo and in vitro,and their two-dimensional electrophoretic resolution

A modification of the two-dimensional electrophoretic method that involves nonequilibrium pH gradients has been adapted for high resolution of chromatin proteins from sea urchin embryos. A simple method of labeling the protein, in vitro, by reductive methylation with boro[³H]hydride to a specific activity of 100,000 cpm/μg of protein is detailed. Chromatin protein may be labeled, in vivo with ¹⁴C-amino acids, and newly synthesized (³H and ¹⁴C-labeled) and preexistent proteins (only ³H labeled) may be distinguished. The method reveals that sea urchin embryo chromatin contains over 200 proteins.     

Arginine8-vasopressin affects catecholamine metabolism in specific brain nuclei

Following the i.c.v. administration of arginine⁸-vasopressin (30 ng in 1 μl saline) to rats that had been injected i.p with α-MPT 30 min prior to the administration of the peptide catecholamine metabolism was altered in a restricted number of brain nuclei. Noradrenaline disappearance was accelerated as compared to saline treated controls in the dorsal septal nucleus, the anterior hypothalamic nucleus, the medial forebrain bundle, the parafascicular nucleus, the dorsal raphe nucleus, the locus coeruleus, the nucleus tractus solitarii and the Al-region. In the supraoptic nucleus and the nucleus ruber a decreased noradrenaline disappearnce was observed after the administration of the peptide. Dopamine disappearance was accelerated in the caudate nucleus, the median eminence, the dorsal raphe nucleus and the A8-region. These results support the view that vasopressin is participating in the regulation of a variety of physiological processes by modulating neurotransmission in specific brain nuclei.     

Localization of glycoprotein glycosyltransferases in the Golgi apparatus of rat and mouse testis

Golgi fractions prepared from rat testis have been shown to be enriched in the following glycoprotein glycosyltransferases: N-acetylglucosaminyltransferase, 47-fold, galactosyltransferase, 33-fold, and N-acetylglucosaminide fucosyltransferase, 15-fold. Appreciably lower transferase levels were obtained in other subcellular fractions. In the mouse, Golgi fractions were prepared from testis homogenates, testis cell suspensions and partially purified testis germinal cells; these fractions were also enriched in the above glycoprotein glycosyltransferases. Electron microscopic analysis indicated that a major portion of the total transferase activity was located in the Golgi apparatus of both rat and mouse testis although these experiments could not rule out the possible presence of some transferase activity in other organelles.     

Deoxyadenosine metabolism and cytotoxicity in cultured mouse T lymphoma cells: a model for immunodeficiency disease.

The inherited absence of either adenosine deaminase (ADA) or purine nucleoside phosphorylase is associated with severe immunological impairment. We have developed a cell culture model using a mouse T cell lymphoma to simulate ADA deficiency and to study the relationship between purine salvage enzymes and immune function. 2′-deoxyadenosine triphosphate (deoxyATP) levels have been shown to be greatly elevated in erythrocytes of immunodeficient, ADA-deficient patients, suggesting that deoxyadenosine is the potentially toxic substrate in ADA deficiency. Using a potent ADA inhibitor, we have demonstrated that deoxyadenosine is growth-inhibitory and cytotoxic to S49 cells, and that deoxyATP accumulates in these cells. Cell variants, unable to transport or phosphorylate deoxyadenosine, are much less sensitive to deoxyadenosine, indicating that intracellular phosphorylation of deoxyadenosine is required for the lethal effects.We have partially reversed the cytotoxic effects of deoxyadenosine with deoxycytidine in wild-type cells, but we cannot show any reversal in cell lines lacking deoxycytidine kinase. Adenosine (ado) kinase-deficient cells are extremely resistant to deoxyadenosine in the presence of deoxycytidine. This deoxycytidine reversal of deoxyadenosine toxicity is consistent with an inhibition of ribonucleotide reductase by deoxyATP, and we have shown that incubation of S49 cells with deoxyadenosine markedly reduces intracellular levels of deoxyCTP, deoxyGTP and TTP.Kinetics data in wild-type cells and in cell variants are consistent with the presence of two deoxyadenosine-phosphorylating activities — one associated with ado kinase and another associated with deoxycytidine kinase.The S49 cells appear to be a valid model for the simulation of ADA deficiency in cell culture, and from our results, we can suggest administration of deoxycytidine as a pharmacological regimen to circumvent the clinicopathologic symptoms in ADA deficiency.     

In vitro sensitization to transplantation antigens. VI. Inhibition of sensitization

We have previously reported that C57BL/6 lymph node cells cultured with C3H/He macrophage monolayers are subsequently able to transfer specific allograft immunity to recipient C57 mice. The present communication is an investigation of the requirement for the functional integrity of cells to mediate allosensitization in vitro and to transfer allograft immunity. Our results indicate that C3H macrophage monolayers subjected to X-irradiation, actinomycin D, or antimacrophage serum pretreatment can no longer sensitize C57 lymph node cells in vitro; supernatants of C3H macrophage cultures do not substitute for monolayered cells and cannot sensitize C57 lymph node cells. The present data also indicate that the integrity of the lymph node cells is required after sensitization in vitro: X-irradiated or sonicated allosensitized lymph node cells do not enable recipient mice to accelerate C3H allograft rejection. The results of this report, therefore, suggest that intact, functionally normal cells are required to sensitize, and to transfer allosensitization.     

Frequency and intensity of chick distress calls: Effects on maternal foodcalling in chickens

The food call of broody domestic hens was used to measure maternal response to four frequency components found in chick distress calls (2,3,4 and 5 kHz) and to variations in distress call intensity (0—86 dB). Foodcalling increased significantly with frequency of the pure-tone test pulse; response to a taped distress call occurred between 40 dB and 86 dB intensity with a maximum at 60–65 dB. The results suggest that the mother uses the higher frequency components in recognizing the distress call, but responds maximally within a specific intensity range. The selective advantage of such behaviour is discussed.     

The influence of retinal on complement-dependent immune damage to liposomes

Retinal was incorporated into liposomes containing dipalmitoyllecithin, cholesterol, dicetyl phosphate and galactocerebroside; the latter substance served as antigen. They were compared to control liposomes, lacking retinal, with regard to glucose release due to complement-dependent immune damage in the presence of anticerebroside serum. The liposomes were indistinguishable from each other in the amount of total glucose trapped, light scattering characteristics and phosphate content. The rate and extent of glucose release in 30 min was inhibited by the incorporation of retinal. In addition, inhibition was directyl related to retinal concentration and was also observed in the presence of a wide range of concentrations of antigen and complement. Damage to liposomes in the presence of either guinea pig or human complement was inhibited by retinal; this was in contrast to the erythrocyte system in which the hemolytic activity of guinea pig complement was inhibited while that of human complement was enhanced by retinal. Addition of retinal to performed liposomes did not influence complement-dependent damage. Inhibition occurred only when retinal was present during the initial formation of the model membranes. Inhibition persisted even after washing the liposomes free of any unincorporated retinal. The data indicate that liposomes may be an excellent model for studying the influences of retinal on complement mechanism in membranes.