Formation of the cysteinyl form of slow reacting substance (leukotriene E4) in human plasma

The two major species of slow reacting substance (SRS) contain either a glutathionyl or cysteinyl-glycyl side chain. Incubation of these SRS's with undiluted or diluted (usually 1:10 or 1:50) human plasma at 37°C resulted in marked losses of smooth muscle contracting activity due primarily to conversion of their oligopeptide side chains to cysteine.     

Metabolism of benzo[a]pyrene and 7,12-dimethylbenz[a]anthracene in cultured human fetal aortic smooth muscle cells.

Cultured human fetal aortic smooth muscle cells derived from the abdominal aorta converted benzo[a]pyrene (BaP) and 7,12-dimethylbenz[a]anthracene (DMBA) $\text{via}$ cytochrome P-450-dependent monooxygenation to metabolites detectable by both a highly sensitive radiometric assay and high pressure liquid chromatography (HPLC). Cells incubated with ³H-BaP transformed this substrate primarily to phenols. ¹⁴C-DMBA was converted to metabolites that cochromatographed with 12-hydroxymethyl-7-methylbenz[a]anthracene, 7-hydroxymethyl-12-methylbenz-[a]anthracene, 7,12-dihydroxymethylbenz[a]anthracene, and trans-8,9-dihydrodiol-7,12-DMBA. Exposure of cells in culture to 13 μM 1,2-benz[a]anthracene resulted in increased oxidative metabolism of both BaP and DMBA. In the case of BaP, total phenol formation was increased, while with DMBA all metabilities detected by HPLC were increased. Support for the potential role of metabolism of polycyclic aromatic hydrocarbons by aortic smooth muscle cells in the etiology of atherosclerosis was obtained.     

Periodic movements of Dictyostelium discoideum sorocarps

We report periodic movements during erection of Dictyostelium discoideum (Dd) sorocarps. Our observations lead to the working hypothesis that Dd sorocarp erection occurs by two superimposed processes: one periodic, with a modal period of 6 1/2 min, and one continuous. We tentatively identify the periodic process with cell movement into the apex of the Dd stalk, and the continuous process with cell vacuolation, together with stalk sheath extension.     

Aggressive behaviour of female prairie deer mice in laboratory populations

Prairie deer mice (Peromyscus maniculatus bairdii), living in asymptotic laboratory populations established two years earlier, were observed for agonistic responses to conspecific intruders. In the first experiment, intruders of six age-sex classes were placed into 10 of the populations for 10 min. The sex of the intruder did not influence the behaviour of the residents, but juveniles elicited more aggression than did adults. A second experiment revealed that female residents were responsible for almost all of the attacks upon juveniles. Experiment 3, in which the responses of pairs of deer mice to juvenile intruders were recorded, demonstrated that the aggressiveness of a female was enhanced by the presence of a male. In the final experiment, females were observed to be highly aggressive during the first few days after giving birth. The aggressive behaviour of the female deer mouse may have greater significance for population dynamics than that of the male.     

Effects of freeze-preservation on some pollen enzymes: II. Freezing and freeze-drying stresses

The isozymes of lily and corn pollen esterases and acid phosphatase were studied in relation to freeze-drying and vacuum-drying. Fresh samples of Lilium longiflorum L. and Zea mays L. pollen were frozen at rates ranging between 200 and 100 °C/min and freeze-dried at temperatures from 0 to ?70 °C for approximately 48 to 70 hr. Freeze-dried samples were rehydrated slowly (10% relative humidity) and rapidly (90% relative humidity). Vacuum-drying was performed at room temperature (22 °C).Soluble pollen enzymes were analyzed by disc electrophoresis on polyacrylamide gels stained with substrate specific reagents. The stained gels were evaluated by densitometry for migration rate, isozyme pattern, and relative activity. The numerical data generated in this manner were then statistically analyzed.The following conclusions resulted from this study: (i) freeze-drying and freeze-thawing treatments were comparable except for corn esterases; (ii) freeze-drying induced alterations in enzyme activity except for corn acid phosphatase; (iii) the freezing rate, the final freezing temperature, and exposure to various relative humidities produced few changes in freeze-dried material; (iv) freeze-drying was less detrimental than vacuum-drying to the enzyme characteristics of corn; (v) freeze-drying yielded higher viabilities than vacuum-drying; and (vi) acid phosphatase alterations appeared to be related to pollen viability in most cases.     

The vocalizations of pygmy marmosets (Cebuella pygmaea)

The vocalizations from a colony of pygmy marmosets are described along with the context in which each was likely to occur. Three contact-location calls were observed to be similar in physical structure, but each appeared in a different context. The ontogeny of these contact-location calls is presented and demonstrates a greater correlation with stages of parental dependence than with chronological age. Alerting and agonistic vocalizations also are described. Many of the vocalizations show close similarity to those of other species of marmosets.     

Artificial insemination of subtropical commercial beef cattle following synchronization with cloprostenol (ICI 80996): I. Fertility

Two trials were conducted over a two-year period with 519 cycling Bos taurus x Bos indicus heifers and cows. The objectives of these trials were: 1) To compare fertility of artificial insemination at the cloprostenol-induced estrus and the naturally occurring estrus, 2) To evaluate the fertility of artificial insemination at a predetermined time (Timed AI) following an estrous synchronization regime with cloprostenol (CLP) and 3) To define the optimum interval from a second CLP treatment for Timed AI. In Trial I, 128 animals were assigned to four treatments: 1) Controls, which were inseminated at the natural occurring estrus; 2) timed AI at 72 hr and again at 96 hr post-second CLP; 3) Timed AI at 72 hr post-second CLP and 4) AI at the CLP-induced estrus. Trial II included 391 heifers distributed among six treatments; 1) Timed AI between 70 and 90 hr post-second CLP; 2) Sham AI between 70 and 90 hr post-second CLP, 3) Chute Stress between 70 and 90 hr post-second CLP; 4) AI at the CLP-induced estrus; 5) Control-AI at the naturally occurring estrus and 6) Non-treated and exposed to fertile bulls. The fertility of the animals artificially inseminated at the CLP-induced estrus was similar to that of insemination at the naturally occurring estrus in Trial I and Trial II (30 vs 46%; 37 vs 38%, respectively). The first service pregnancy rates of the animals bred at a predetermined time were similar to those bred at the CLP-induced estrus in Trial I, but lower in Trial II (P < .01).     

Sequential conversion of the glutathionyl side chain of slow reacting substance (SRS) to cysteinyl-glycine and cysteine in rat basophilic leukemia cells stimulated with A-23187

In rat basophilic leukemia (RBL-1) cells stimulated with A-23187, the major slow reacting substance (SRS) species contain glutathione, cysteinyl-glycine, or cysteine in their side chains, corresponding or closely related to leukotrienes LTC₄, LTD₄, and LTE₄, respectively.³ Evidence is presented that most of the SRS produced during the first few minutes of stimulation by the ionophore has a glutathionyl side chain which is sequentially converted to cysteinyl-glycine and cysteine.     

Reconstitution of the purified calmodulin-dependent (Ca2+ + Mg2+)-ATPase from smooth muscle

The purified calmodulin dependent (Ca2+ + Mg2+)-ATPase (CaMg ATPase) from porcine antral smooth muscle transports Ca2+ after reconstitution in lipid vesicles indicating that this enzyme is indeed a Ca2+-transport ATPase. For CaMg ATPase reconstituted in asolectin vesicles a good correlation was found between the time course of Ca2+ accumulation and the corresponding changes in CaMg ATPase activity. The ATPase activity was stimulated 8-fold by A23187, which further indicates a tight coupling between ATP hydrolysis and Ca2+ transport. Asolectin vesicles with incorporated enzyme accumulated Ca2+ with a ratio approaching one Ca2+ ion transported for each ATP hydrolyzed. For CaMg ATPase reconstituted in phosphatidylcholine vesicles on the other hand, Ca2+ transport and CaMg ATPase were poorly coupled as is shown by the approximately 3.5 fold stimulation by A23187. The activity of the CaMg ATPase when reconstituted in asolectin vesicles was stimulated 1.25 fold by calmodulin while in phosphatidylcholine a value of 4.25 was obtained. The CaMg ATPase activity of the enzyme reconstituted either in asolectin or phosphatidylcholine was, after its stimulation by A23187, still further stimulated by detergent by a factor of 5.     

Artificial insemination of subtropical commercial beef cattle following synchronization with cloprostenol (ICI 80996): II. Estrous response

Data collected from two controlled breeding field trials involving 561 Bos indicus x Bos taurus cows and heifers were analyzed for estrous and fertility response following a cloprostenol ICI-80, 996 (CLP) synchronization regime. Fertility data were discussed in a companion paper (1). In Trial 1, 128 animals were assigned to four treatments: 1) controls which were inseminated at the naturally occurring estrus; 2) Animals artificially inseminated at approximately 72 hr and 96 hr following a second CLP; 3) Animals artificially inseminated at approximately 72 hr following a second CLP; and 4) Animals artificially inseminated approximately 12 hr after detection of estrus post-second CLP. Trial II included 391 heifers distributed among six treatments: 1) Artificially inseminated between 70 and 90 hr post-second CLP; 2) Sham inseminated between 70 and 90 hr post-second CLP; 3) Processed with no manipulation of the genital tract between 70 and 90 hr post-second CLP; 4) Artificially inseminated approximately 12 hr after the detection of estrus following a second CLP; 5) Artificially inseminated at the naturally occurring estrus and 6) Non-treated heifers exposed to fertile bulls. Cloprostenol ICI-80996 was effective (P < .01) in synchronizing estrus in comparisons of treated vs non-treated controls in Trials I and II (82 vs 29%; 57 vs 19%, respectively). However, a significant reduction in the expression of estrus was observed following Timed AI when compared to heifers bred 12 hr after detection of CLP-induced estrus in Trial II (37 vs 54%, P < .05). The authors conclude that a single timed insemination of Brahman crossbred heifers suppresses the behavioral expression of estrus. Other evidence (1) indicates that the fertility during this period is similarly reduced.     

Localization of a site interacting with human platelet receptor on carboxy-terminal segment of human fibrinogen gamma chain

We report that the 27-residue carboxy-terminal cyanogen bromide fragment of human fibrinogen γ chain inhibits binding of [¹²⁵I]fibrinogen to human platelet receptors and blocks fibrinogen-mediated aggregation of ADP-treated human platelets. The blocking activity of the peptide was preserved after proteolysis of the isolated peptide with staphylococcal protease to generate a mixture of a dodecapeptide and a pentadecapeptide. Trypsin treatment destroyed blocking activity of the isolated peptide. These results indicate that the site responsible for the interaction of human fibrinogen with the platelet receptor resides in the 27-residue carboxy-terminal region of the γ chain.     

Arylsulfatase inactivation of slow reacting substance. Evidence for proteolysis as a major mechanism when ordinary commercial preparations of the enzyme are used

Type II B arylsulfatases are known to inactivate slow reacting substance (SRS), but the mechanism is unclear. In the present study, ordinary commercial preparations of Sigma limpet arylsulfatase largely inactivated the glutathionyl and cysteinyl-glycyl forms of SRS, but the cysteinyl form of SRS was largely resistant to the enzyme. Evidence is presented which established that a major mechanism for the inactivation of the glutathionyl and cysteinyl-glycyl SRS types, at least by the particular enzyme preparations we have studied, involves cleavage of the glycine moiety from the sulfur containing side chain. This was confirmed by digestion studies with glutathione itself. In addition, there is ome evidence to indicate that the enzyme may destabilize the double bond structure of the SRS molecule, contributing to the overall inactivation.     

Experimental studies on a mutant gene (e) preventing the differentiation of eye and normal hypothalamus primordia in the axolotl

The phenotype of axolotls (Ambystoma mexicanum) homozygous for the mutant gene e (“eyeless”) is different from normal in that (1) no optic vesicles develop in $\text{e}\text{e}$ embryos, (2) $\text{e}\text{e}$ larvae from posthatching onward are darker than normal white larvae, and (3) fully grown $\text{e}\text{e}$ animals are sterile.Experiments reported here show that eyelessness in $\text{e}\text{e}$ embryos results from a direct effect of the gene on presumptive forebrain ectoderm; not on the mesoderm that induces the ectoderm to form eyes. Homotopic grafts of normal presumptive ectoderm on $\text{e}\text{e}$ blastula hosts differentiated complete eyes, but reciprocally grafted embryos were always eyeless. Similarly, grafts of either $\text{e}\text{e}$ or normal presumptive prechordal mesoderm into normal hosts gave normal eyes, but in the mutant hosts no eyes developed. Thus the e gene affects only the ectodermal component of the inductive system for eye formation.Genetically eyeless (pigmented) cells, when interspersed prior to gastrulation among genetically eyed (albino) cells in the eye preprimordium, are induced to form clones of pigmented retinal epithelium in the albino host eye.The sterility of $\text{e}\text{e}$ larvae appears also to be due to a direct effect of the e gene on the ectodermal (neural plate) primordium of the hypothalamus. Grafts of normal cells which included the hypothalamic, but not the optic or anterior pituitary primordia, always restored fertility to $\text{e}\text{e}$ recipients.The mutant pigmentation phenotype was demonstrated to be a consequence of eyelessness and, therefore, an indirect effect of the gene. The pigment pattern of normal embryos from which both optic vesicles were removed resembles that of the mutants. In addition, implantation of a single full-sized, functional eye was able to restore the normal pigmentation, but not fertility, to $\text{e}\text{e}$ recipients.     

Perception of simulated stars by Eptesicus fuscus (Vespertilionidae): A potential navigational mechanism

Three big borwn bats, Eptesicus fuscus, were trained, using a behavioural discrimination technique, to respond to a point light source. Stimulus presentations were separated by randomly determined, variable time sequences. The star simulator, 100 cm from the subject, approximated the spectral energies of the blue and white star classes for intensities in the scotopic visual range. The data indicate a stellar threshold level of +3.2 magnitudes, suggesting that stars could serve as navigational cues for these bats.     

(2R*, 3S*)-1-[18F]fluoro-2,3-bis(4-hydroxyphenyl)pentane [( 18F]fluoronor-hexestrol), a positron-emitting estrogen that shows highly-selective, receptor-mediated uptake by target tissues in vivo

The positron-emitting, non-steroidal estrogen (2R*, 3S*)-1-[18F]fluoro-2,3-bis(4-hydroxyphenyl)pentane [( 18F]-fluoronor-hexestrol), has been prepared by fluoride ion displacement on a labile trifluoromethanesulfonate (triflate) derivative of a suitably protected precursor, followed by removal of the aryl triflate groups with lithium aluminum hydride and purification by HPLC. In immature female rats, this compound is taken up selectively by the uterus and is retained for prolonged periods, due to its binding to the estrogen receptor. This compound and related 18F-labeled estrogens thus appear to be promising agents for imaging estrogen receptor-positive breast tumors in humans.     

Endocytosis in Chinese hamster fibroblasts : Inhibition by glucose

Endocytosis in Chinese hamster ovary fibroblasts was investigated by measuring the rate of uptake of ³H-sucrose, which is known to enter cells only by endocytosis. Serum, polyvinylpyrrolidone (PVP), adenosine triphosphate, insulin, and cyclic 3′,5′-adenosine monophosphate, all of which are known to increase the rate of endocytosis by other cell systems, had no effect on Chinese hamster fibroblasts. However, medium in which these cells had been maintained for several days, referred to as conditioned medium, had a profound effect on endocytosis. These cells endocytosed 3 to 5 times as rapidly in conditioned medium as in fresh medium. A logarithmic inhibition of this effect was observed with increasing -glucose concentrations, however, glucose-free medium did not produce as great an effect as conditioned medium. This suggests that these cells may endocytose in response to their nutritional requirements.     

Bovine plasma progesterone levels at programmed circadian temperatures of 17 to 21 degrees C and 21 to 34 degrees C

Eight Angus heifers were subjected to control ambient temperatures (diurnal variation of 17 to 21°C) and experimental ambient temperatures (diurnal variation of 21 to 34°C). There was no significant difference (P > 0.05) in progesterone levels between the two environmental regimes or blood samples collected at 0800 and 1600 hr.