Eimeria tenella: specific reversal of t-butylaminoethanol toxicity for parasite and host by choline and dimethylaminoethanol.

t-Butylaminoethanol is an anticoccidial compound that is related structurally to the metabolically active substances, dimethylaminoethanol, and choline. Toxic effects of t-butylaminoethanol for chickens and Eimeria tenella are specifically overcome by feeding sufficient amounts of dimethylaminoethanol or choline. Dietary concentrations of the two above metabolites required to totally overcome toxic effiects of t-butylaminoethanol were determined and are expressed as the reversal ratio, inhibitor (t-butylamino-ethanol): metabolite. The inhibitor:choline ratio for total reversal of toxic effects of the inhibitor in chickens is approximately 1:10 over a concentration range of inhibitor from 0.019 to 0.05%. The inhibitor:choline ratio for reversal of antiparasitic effects is approximately 1:200 with a concentration of 0.01% inhibitor. The inhibitor:Dimethylaminoethanol ratio for reversal of toxic effects of the inhibitor in the chicken is approximately 1:7 with a concentration of 0.015% inhibitor. The inhibitor:dimethylaminoethanol ratio for reversal of antiparasitic effects is approxmately 1:20 wth a concentration of 0.01% inhibitor.     

A quantitative cytochemical study of glucose-6-phosphate dehydrogenase and Δ 5-3β-hydroxysteroid dehydrogenase activity in the Membrana granulosa of the ovulable type of follicle of the rat

Summary During the last four days of follicular development prior to ovulation, the activities of ⁵-3-hydroxysteroid dehydrogenase (3OHD) and glucose-6-phosphate dehydrogenase (G-6-PD) were quantified in cryostat sections of the rat ovary. The product of the enzyme reactions were measured using a scanning and integrating microdensitometer. The enzyme activity was measured in the peripheral region, the antral region and the cumulus of the membrana granulosa (MG) of these follicles on the morning of each of the four days of the estrous cycle. G-6-PD activity was measured in the presence and absence of an intermediate hydrogen acceptor, phenazine methosulphate, to provide a measure of the quantity of Type I and Type II Hydrogen (H) generated: Type I H is considered to be related to hydroxylating reactions such as those of steroids and Type II H to other general biosynthetic activities of cells.In all three regions of the MG of follicles of the ovulable type, 3OHD activity was lowest in estrus and diestrus-1, increased on diestrus-2 and peaked in proestrus. In estrus and diestrus-1, the level of 3OHD activity in the three regions was comparable. However, by diestrus-2, and even more conspicuously in proestrus, enzyme activity was significantly greater in the peripheral region than in the antral region or in the cumulus. During the same period, the level of enzyme activity remained comparable in the last two regions. Throughout the estrous cycle, both Type I and Type II H generation from G-6-PD was greatest in the peripheral region, less in the antral region and least in the cumulus. In the peripheral region, Type I H generation increased progressively after diestrus-1, to reach a maximum in proestrus. In the antral region, Type I H generation increased between diestrus-1 and diestrus-2 and then remained unchanged through proestrus. In the cumulus, Type I H generation remained at levels seen in estrus throughout the remainder of the cycle. Generation of Type II H, in the peripheral region was constant throughout the estrous cycle. In contrast, in the antral region and cumulus, Type II H generation was greater in diestrus-1 and diestrus-2 than on either proestrus or estrus.This work was supported by research grants from the National Institute of Child Health and Human Development (# HD-12684) and (# HD-09542) and from the Rockefeller Foundation     

Behavioural displays to gustatory stimuli in newborn rabbit pups

Motor displays in the face and head regions of 33 neonate rabbits(less than 24 hrs post partum) in response to taste stimulationwere examined. A droplet of taste solution was placed mediallyon the pup's lips and the ensuing behavioral repertoire wastallied over a 60 sec period in a double blind situation. Tastantsincluded 2 concentrations each of sucrose, saccharin, citricacid and quinine. Distilled water was used as a stimulant andfor intertrial rinses. Response characteristics to the varioustaste stimuli were differentiable, specific and reproduciblewithin and across animals. Certain response features were moreoften associated with one stimulus than with another. Quinineoften produced mouth opening (gaping) and head movements, whereassucrose was associated with a quiet animal licking and makingcharacteristic mouth movements. Sour reactions often resembledthose to sweet, but other features helped distinguish thoseresponses. Reactions proved to be concentration-dependent anddifferent from those to water. Quality and hedonic value wereusually accurately judged and corresponded to adult preferencebehaviors. It was inferred that rabbits at this early age arealready equipped with a functioning taste system up to the brainstemlevel. Cross-species comparisons of stereotyped reactions werediscussed.     

Uterine prostaglandin levels following stimulation of the decidual cell reaction: Effects of indomethacin and tranylcypromine

Prostaglandin E (PGE) and F (PGF) levels were measured in mouse uteri at various times after either trauma (hemostat crushing) or oil stimulation of the decidual cell reaction (DCR). The oil induced DCR led to an early increase (within 5 min) in both PGE and PGF levels. Both returned to baseline by 1 h after stimulation. A second peak in PGF levels was observed at 120 min after oil stimulation. This study demonstrates a distinct difference between the pattern of PGE and PGF changes in the uterus following oil stimulation of the DCR. Indomethacin pretreatment completely blocked the oil stimulated DCR as well as all prostaglandin increases following either stimulus. The trauma stimulated DCR was not completely blocked by indomethacin pretreatment.Pretreatment with tranylcypromine, an inhibitor of prostacyclin biosynthesis, did not block the prostaglandin E and F increases, but did block the oil stimulated DCR. These findings suggest that prostacyclin may be an early mediator of the DCR.     

The zinc content of yeast alcohol dehydrogenase

Analyses for zinc in high specific activity preparations of yeast alcohol dehydrogenase (YADH) indicate a metal content of 1.8–1.9 moles of zinc per mole of enzyme subunit. This zinc content is observed for YADH prepared from Bakers yeast by recrystallization from Am₂SO₄ containing 1 mM EDTA, followed by chromatography on DE-52 and Sephadex-G-200. YADH obtained from Boehringer-Mannheim is characterized by a variable specific activity: preparations with Sp. Ac. = 380–400 U/mg contain 1.8–1.9 moles of zinc per mole of subunit. Dialysis of YADH against EDTA (pH 8.5, 25°, under N₂) reduces the specific activity and zinc content in an approximately linear fashion down to a Sp. Ac. = 150 U/mg, consistent with the preferential loss of a single, weakly bound zinc per subunit which is essential for catalytic activity. Dialysis of YADH against 1 mM ZnCl₂ (pH 6.5–8.5, 25°, under N₂) does not lead to an increase in the zinc content of the enzyme, indicating that under these conditions zinc does not bind adventitiously to YADH. Dialysis against 50 mM CoSO₄ (pH 5.5, 25°, under N2, 60–90 hr) leads to an exchange of ≈ 40% of the enzyme-bound zinc by cobalt. Our preparations of YADH are consistently characterized by a zinc content of ≈ 2 per subunit and we are unable to reduce the zinc content of YADH by dialysis against EDTA without a concomitant loss in enzyme activity, in contrast to reports of one zinc per subunit [Veillon, C. and Sytkowski, A.J., BBRC $\text{67}$: 1499 (1975); Vallee, B.L. and Hoch, F.L., Proc. Nat. Acad. Sci. USA $\text{41}$: 327 (1955)]. The findings reported here, together with the observed structural similarities between YADH and horse liver alcohol dehydrogenase [Jornvall, H., Woenckhaus, C. and Johnscher, G., Eur. J. Biochem. $\text{53}$: 71 (1975)], suggest a role for zinc at both a structural and catalytic site in YADH.     

Similarities in properties and a functional difference in purified leucyl-tRNA synthetase isolated from two developmental stages of Tenebrio molitor

In Tenebrio molitor, as well as in other biological systems, there are indications that differences in leucyl-tRNA synthetase activity may play a role in translational control. However, it has not been clear whether the difference in activity is due to the appearance of a multiplicity of enzymes during development or to the alteration of a single enzyme.The purification of leucyl-tRNA synthetase from day 1 and day 7 after the larval pupal molt of Tenebrio molitor is described. The enzyme from both developmental stages was purified over a 1000-fold. The two enzyme preparations are identical in molecular weight (99,000). They show the same characteristics after aging. The pH optimum, heat inactivation behavior, and dependency on divalent cations are the same for both enzymes. They also show identical kinetics with similar values of Km for leucine, ATP, Mg²⁺, and tRNA day 1. However, leucyl-tRNA synthetase purified from day 7 exhibits an additional function in recognizing a new species of isoaccepting tRNA in day 7 tRNA. We have tentatively concluded that the two enzymes are probably different forms of the same enzyme and the additional activity is due to alteration of the enzyme at the macromolecular level during development.     

Postpartum,hormonal, and nonhormonal induction of maternal behavior in rats: Effects on T-maze retrieval of pups

It is known that the home-cage maternal behavior of rats which become maternal after daily pup exposure (sensitization) is almost indistinguishable from that of lactating mothers, but that sensitized and lactating rats can be distinguished by their pup-retrieval performance in a T-maze extension of the home cage. The present study explored this difference further. Postpartum mothers which could not suckle due to prior nipple removal (thelectomy) retrieved as well, if not better, than intact controls in the T-maze. Hormonal induction of maternal behavior (in ? 3 days) was carried out by hysterectomy-ovariectomy plus 100 μg/kg estradiol benzoate; the performance of these females was similar to that of the postpartum groups. In contrast, only a small percentage of the sensitized mothers retrieved in the T-maze, whether the latency to onset of their maternal behavior was long (4–10 days) or short (? 3 days). Thus, hormonal factors associated with pregnancy and/or parturition, but not suckling stimulation, may facilitate T-maze retrieval of pups. The possible ethological significance of the T-maze test as a measure of maternal responsiveness is discussed.     

ECOLOGY AND NATURAL HISTORY OF IRIDAEA CORDATA (RHODOPHYTA; GIGARTINACEAE): POPULATION STRUCTURE1

The population structure of 4 California Iridaea cordata (Turner) Bory populations was studied. Random sampling procedures were used to measure seasonal variations in standing crops, density and size-class distribution of life history stages. The results describe aspects of the in situ life history; a prerequisite to realistically considering the distribution, ecology or life history expressions of an alga. Seasonal fluctuations in density occur only in the juvenile stage, which is initiated during the winter (November to January) predominantly from the basal perennial crusts. Both the gametangial and tetrasporangial stages are present throughout the year. The tetrasporangial stage is dominant in relation to the sexual stages in both density and biomass during most of the year, except spring when the new crop in just maturing and all stages are abundant. Density in nearly constant and observable changes in the populations are due to biomass fluctuations. Seasonal lows in biomass occur during the winter with the majority of thalli in the smaller size-classes. Growth and maturation culminate in peak summer crops and dominance of the tetrasporangial stage, followed by autumnal senescence and die-back in winter. Carrageenans analyzed from immature thalli showed a predominance of lambda-type, previously determined as specific for tetrasporangial plants. This indirect evidence for the tetrasporangial nature of immature plants suggests that dominance of the diploid stage occurred prior to blade development and most likely at the spore level. Alternatively, field results indicate a major contribution and possible replacement of alternation of gametangial and tetrasporangial stage by thallus perennation and vegetative reproduction.