Vitellogenin, lipid and carbohydrate metabolism during vitellogenesis and pregnancy, and after hormonal induction in the blenny Zoarces viviparus (L.).

1. Ovarian vitellogenic growth in Zoarces viviparus lasts about 2 months. Vitellogenesis is immediately followed by ovulation, fertilization and a pregnancy period of 4 months. Vitellogenin is observed in the blood during vitellogenesis, but declines during the first month of pregnancy. 2. The largest amount of liver lipid is found before vitellogenesis is initiated. During pregnancy the liver is depleted of lipid and glycogen, and total lipid and phospholipid is accumulating in the blood. 3. Estradiol treatment during pregnancy results in a dose-dependent increase in vitellogenin and lipids of the blood. 4. In late pregnancy, birth can be provoked with progesterone alone, or with combined progesterone and estradiol treatment.     

Estrogen metabolism in the equine conceptus and endometrium during early pregnancy in relation to estrogen concentrations in yolk-sac fluid

Because estradiol (E(2)) production by the early equine conceptus is considered crucial to the establishment of pregnancy, the amounts of E(2), estrone (E(1)), and their sulfates (E(2)S, E(1)S) were measured by RIA in yolk-sac fluid of 63 conceptuses collected by transcervical lavage over the period of 11-26 days after ovulation. Amounts increased significantly with age of conceptus, especially for E(1)S. Then, the metabolism of E(2), which may be highly relevant for its action, was examined in the conceptus and endometrium over the period when the conceptus ceases to migrate within the uterus. Eleven conceptuses collected mainly on Days 12, 15, and 18, with endometrial biopsy samples taken immediately thereafter, were used for steroid metabolic studies. Trophoblastic and endometrial tissues were incubated with [(3)H]-labeled E(2) or E(1), and with [(14)C]-E(1) in one experiment. Steroids were recovered from the media by solid-phase extraction (SPE) and eluted separately as unconjugated and conjugated fractions. Conjugation increased from Day 12 for the trophoblast (more so by bilaminar than trilaminar tissues on Day 18) and was much greater for endometrium, with almost all as sulfoconjugates. HPLC profiles of free and sulfate fractions were obtained from a gradient of acetonitrile/water. Interconversion (E(2) right harpoon over left harpoon E(1)) by trophoblast varied with development; it favored E(2) in older conceptuses, more in bilaminar than trilaminar tissues. Some more polar products were also noted, with loss of tritium seen as [(3)H](2)O at SPE, and confirmed by HPLC in a second system with authentic reference steroids. Almost all radioactivity in the endometrium was present as E(2) in both free and sulfate fractions. It was concluded that local metabolism of E(2) is quantitatively significant and may play an important role in the actions of the large amounts of estradiol produced by the early equine conceptus.     

Glucose metabolism in vivo in crossbred Holstein cattle feeding on different types of roughage during late pregnancy and early lactation

An experiment was carried out to study the glucose kinetics of crossbred Holstein cattle feeding on either hay or 5% urea treated rice straw during late pregnancy (21 days prepartum) and early lactation (30 days postpartum). In all 16 pregnant heifers (23–25 months of age) were selected for the experiments, including eight animals of two breed types, Holstein Friesian×Red Sindhi (50:50=50% HF) and Holstein Friesian×Red Sindhi (87.5:12.5=87.5% HF). They were divided into four groups of four animals each. Animals from the same breed type in each group were fed with either rice straw treated with 5% urea or pangola hay (Digitaria decumbens) as the source of roughage throughout the experiments. The glucose turnover rate in both types of crossbred Holstein cattle was determined using a continuous infusion of [U-¹⁴C] and 3-[³H]glucose during late pregnancy and early lactation. Total glucose entry and utilization rates increased significantly during lactation for all groups. Recycling of [C]glucose was, approximately, 20% in both crossbred cattle fed either hay or urea treated rice straw and was unaffected by the stage of late pregnancy or early lactation. Comparing 50 and 87.5% HF animals, arterial plasma glucose concentrations were slightly higher during pregnant periods but significantly higher in lactating periods in 50% HF animals. The ratio of specific radioactivity of arterial blood bicarbonate relative to that of arterial blood [¹⁴C]glucose in the lactating period, significantly decreased in 50% HF animals fed either urea treated rice straw or hay. An increase in udder blood flow during early lactation was significantly higher in 87.5% HF animals than in 50% HF animals. The uptake, arteriovenous differences and extraction ratio for glucose across the udder, significantly increased in the lactating period for all crossbred animals. Glucose uptake by the udder of 87.5% HF animals accounted for 65% of the total glucose turnover rate compared to a value of 46% in the lactating 50% HF animals. It can be concluded that both crossbred cattle fed either urea treated rice straw or hay exhibit the same body glucose turnover rate. The 87.5% HF animal has the genetic potential for a high milk yield and has high body and udder glucose metabolisms compared with 50% HF animals.     

Quantitative cytochemical analyses of ovarian luteal and interstitial cell RNA in relation to plasma progestins during pseudopregnancy in the rat

Luteal and interstial cell RNA contents and circulating progesterone (P) and 20α-hydroxypregn-4-ene-3-one (20α-OH P) levels were measured during pseudopregnancy in order to characterize relationships between ovarian 20α-OH P secretion and luteal regression. Functional luteolysis, as manifested in depressed P levels, was not associated with concurrent elevations in 20α-OH P. Rather, augmented 20α-OH P levels were evidenced in periovulatory periods at the onset and termination of pseudopregnancy, subsequent to RNA accumulation in both luteal and interstitial compartments. It is postulated that 20α-OH P, the putative inactive metabolite of P, is produced by both ovarian compartments in a cyclic manner and in response to gonadotrophin released in the preovulatory period.     

Proteins synthesized and secreted by the guinea-pig conceptus during early pregnancy in relation to corpus luteal maintenance.

Guinea-pig conceptuses obtained on Day 15 of pregnancy were cultured for 24 h in the presence of [3H]leucine. Proteins present in the culture medium were purified by dialysis, desalted, and subjected to analysis by gel filtration chromatography, ion-exchange chromatography, and polyacrylamide gel electrophoresis. The major non-radioactive protein present co-chromatographed with serum albumin. Fresh protein synthesis occurred as indicated by the incorporation of [3H]leucine, and the proteins produced were acidic in nature. Many radioactive proteins in relatively similar amounts were produced, with protein of molecular weights 28.8 and 98.2 kDa (as determined on Sephacryl S-300HR) and of molecular weights 8.4 and 14.7 kDa (as determined on Sephadex G-75SF) being synthesized in marginally greater quantities. Consequently, from the profile of proteins synthesized and secreted, no obvious candidate emerged as the anti-luteolytic factor synthesized and secreted by the guinea-pig conceptus during early pregnancy which inhibits endometrial PGF2 alpha synthesis and maintains corpus luteal function.     

Role of ascorbic acid in metabolism of rat testis and epididymis in relation to the onset of puberty

The metabolism of ascorbic acid, cholesterol, serum testosterone level and activities of 3Β and 17Β hydroxysteroid dehydrogenases were studied in testis and Cauda epididymis of prepubertal, pubertal and postpubertal (5, 15, 30, 45, 55 and 60 day old) rats. The data showed that serum testosterone levels and 3Β and 17Β hydroxysteroid dehydrogenases were increased with the age. The ascorbic acid metabolism was found to be stabilized in testis at day 30 being comparable with the adult, whereas a spurt in its metabolism occurred by day 45 and a significant depletion in ascorbic acid content in relation to the passage of the first wave of spermatozoa through cauda epididymis. The results of this study clearly elucidate that ascorbic acid is involved in metabolism of testis and epididymis in developing postnatal rats, in relation to the increasing demands for attaining a stable hormonal milieu, and the onset of puberty and the passage of the first wave of spermatozoa,via the formation of its free radical monodehydroascorbic acid and charge transfer complex mechanism     

Adenosine deaminase activity in relation to the appearance of early and late Epstein-Barr virus antigens induced in lymphoblastoid cells

Summary Induction of Epstein-Barr virus (EBV) capsid antigen synthesis in 59.6% of P3HR-1 cells was followed by a decrease to 70% in adenosine deaminase (ADA) activity. In Daudi cells synthesizing EBV early antigen, ADA activity did not decrease.     

Calcium and oxalate content of the leaves of Phaseolus vulgaris at different calcium supply in relation to calcium oxalate crystal formation

Soluble and insoluble oxalate and insoluble calcium were measured in the leaves of Phaseolus vulgaris. The plants were grown in nutrient solutions with two different concentrations of calcium. Two developmental stages of the leaves were studied. Although the content of insoluble calcium differs widely according to leaf age and growth conditions, the percentage bound in crystals is nearly the same in all cases. In the growing leaves, concentrations of total oxalate are independent of calcium supply, thus, showing that the known rise in numbers of crystals, and of cells containing them, is not induced via oxalate biosynthesis. Fully expanded leaves contain more oxalate when grown in a nutrient solution with higher calcium concentration. Amounts of oxalate in percent of dry weight are similar to those given in the literature for other legume leaves.     

Seasonal variations in intermediatory metabolism of the bivalves Cerastoderma edule and Scrobicularia plana during exposure to air

Seasonal changes in the operation of the succinate pathway by different tissues of two species of bivalve molluscs (Cerastoderma edule (L.) and Scrobicularia plana) were investigated. No significant changes were observed in tissues of C. edule. However, there were significant seasonal changes in the operation of the pathway by tissues of S. plana. The succinate pathway operates in S. plana at a higher rate in summer and autumn than in witer. The results are discussed in relation to food availability, temperature and the reproductive cycle.     

Haptoglobin and CCR2 receptor expression in ovarian cancer cells that were exposed to ascitic fluid: Exploring a new role of haptoglobin in the tumoral microenvironment

Haptoglobin (Hp) is an acute-phase protein that is produced by the liver to capture the iron that is present in the blood circulation, thus avoiding its accumulation in the blood. Moreover, Hp has been detected in a wide variety of tissues, in which it performs various functions. In addition, this protein is considered a potential biomarker in many diseases, such as cancer, including ovarian carcinoma; however, its participation in the cancerous processes has not yet been determined. The objective of this work was to demonstrate the expression of Hp and its receptor CCR2 in the ovarian cancer cells and its possible involvement in the process of cell migration through changes in the rearrangement of the actin cytoskeleton using western blot and wound-healing assays and confirming by confocal microscopy. Ovarian cancer cells express both Hp and its receptor CCR2 but only after exposure to ascitic fluid, inducing moderated cell migration. However, when the cells are exposed to exogenous Hp, the expression of CCR2 is induced together with drastic changes in the actin cytoskeleton rearrangement. At the same time, Hp induced cell migration in a much more efficient manner than did ascitic fluid. These effects were blocked when the CCR2 synthetic antagonist RS102895 was used to pretreat the cells. These results suggest that Hp-induced changes in the cell morphology, actin cytoskeleton structure, and migration ability of tumor cells, is possibly “preparing” these cells for the potential induction of the metastatic phenotype.     

The inseminating bull and plasma pregnancy-associated glycoprotein (PAG) levels were related to peripheral leukocyte counts during the late pregnancy/early postpartum period in high-producing dairy cows

It has been established that the immunologic and endocrine status of the peripartum dairy cow determines the animal's subsequent productive and reproductive performance. Thus, at parturition reduced immune functions of peripheral blood polymorphonuclear cells (PMN) has been observed after a peak in pregnancy-associated glycoproteins (PAGs), and, more recently, the inseminating bull was linked to plasma levels of bovine PAGs in pregnant Holstein-Friesian dairy cows. The present study sought to determine whether changes in leukocyte counts during the peripartum period, indicative of the animal's immune status, could be related to the inseminating bull and to PAG levels. Ninety-six clinically healthy, single pregnant cows in a commercial dairy herd were selected. Four samples were collected before parturition (on gestation Days 220-226, 234-240, 248-254, and 262-268) and two samples after parturition (on Days 14-21, and 28-34 postpartum) to analyze total and differential blood cell counts. Based on GLM analysis procedures of variance for repeated measures, the inseminating bull was found to affect counts of total leukocytes and lymphocytes (P < 0.001; between-subject effects) throughout the peripartum period. In addition, cows with high plasma PAG levels (> 900 ng/ml) on Day 262-268 of gestation had higher numbers of total leukocytes and neutrophils throughout the peripartum (P < 0.001; between-subject effects). Young animals (≤ 1 lactation) had higher total leukocyte and lymphocyte counts than older cows (2 or more lactations) throughout the study period. These results reveal a clear relationship between the inseminating bull or plasma PAG levels and peripheral leukocyte counts during the peripartum period in dairy cows.     

Hypothalamic metabolism of neurotransmitters (serotonin,norepinephrine, dopamine) and NPY,and gonadal and adrenal activities,during the early postnatal period in the rat

It is noteworthy that in the rat the early postnatal life is marked by an activation of both the corticostimulating function of the adenohypophysis in neonates of both sexes and of the gonadostimulating function mainly in males. In order to specify if such neuroendocrine variations are temporally correlated with changes in the hypothalamic metabolism of neurotransmitters, the hypothalamic metabolism of serotonin (5 HT), norepinephrine (NE), and dopamine (DA) and the hypothalamic content of neuropeptide Y (NPY) have been investigated in newborn rats of both sexes, delivered at term by cesarean section, as well as changes in the activity of both the hypothalamo-pituitary adrenal axis (HPA) and the hypothalamo-pituitary gonadal axis (HPG). Experimental data suggested that 1) in males a rise in hypothalamic metabolism of 5 HT, NE and DA occurs during the first two hours after delivery, whereas in females, only the metabolism of NE increases. Moreover, the postnatal metabolism of NE was higher in females than in littermate males; 2) NPY content of the hypothalamus, which was at birth significantly higher in males than in females, dropped in the former but not in the latter; 3) in newborn males, an early surge of plasma testosterone occurs, suggesting postnatal activation of the HPG axis; on the other hand, in females, a late and slight increase in plasma estradiol is observed; 4) in early postnatal life, a sex-independent rise in plasma ACTH and adrenal and plasma corticosterone levels suggest a comparable activation of the HPA axis in newborns of both sexes. In conclusion, the early postnatal activation of the corticostimulating function in neonates of both sexes and that of the gonadostimulating function, mainly in males, could be temporally correlated with a rise in the hypothalamic metabolism of two neurotransmitters, 5 HT and NE, and of NPY content. According to our data, a sex-dependent metabolsim of neurotransmitters in the hypothalamus is already apparent in early postnatal life.     

Changes in the levels of abscisic acid and its glucose ester conjugate during maturation of hybrid larch (Larix × leptoeuropaea) somatic embryos, in relation to germination and plantlet recovery

Changes in abscisic acid content during maturation of hybrid larch somatic embryos ( Larix × leptoeuropaea ), were followed using an enzyme immunoassay (ELISA). In the presence of 60 μ M cis-trans (±)-ABA in the maturation medium, the cis-trans (±)-ABA level of the somatic embryos in planta increased during the maturation phase to reach a maximum value at week 5. Concomitantly, an extension of the period of maturation from 3 to 4 and 5 weeks resulted in a significant decrease in both germination and plantlet frequencies. As a consequence, we assume that it was the level of ABA in planta that was responsible for the inhibition. ABA acted in both a stimulatory and an inhibitory manner. If ABA promoted the obtention of high quality somatic embryos in large numbers, it also had a deleterious effect on the subsequent development, i.e. germination and plantlet recovery. The results stressed the importance of both the procedure and duration of maturation.     

Carbon metabolism in the subantarctic Kerguelen cabbage Pringlea antiscorbutica R. Br.: environmental controls over carbohydrates and proline contents and relation to phenology

The subantarctic Brassicaceae Pringlea antiscorbutica R. Br. (Kerguelen cabbage) was used as a model to study the physiological adaptations of higher plants to the subantarctic environment. ¹³C-nuclear magnetic resonance permitted, in combination with biochemical methods, the identification and quantification of the major solutes in leaves, stem and roots. As characterized in many Brassicaceae, proline was a major solute in all organs of the plants, and its accumulation was mainly controlled by salt stress rather than temperature. Glucose was the major soluble sugar in the leaves, whilst sucrose and starch accumulated in stems and roots. Over a period of 1 year we found strong correlations between (i) glucose content in leaves and irradiance, and (ii) starch content in non-photosynthetic organs and air temperature. The pattern of carbohydrate accumulation indirectly indicated that photosynthetis was sustained throughout the year, even during cold days when the temperature remained near 0 °C. This is consistent with the direct gas exchange measurements showing that photosynthetic capacity is mainly influenced by irradiance and weakly by temperature. Taken together, these characteristics demonstrated that the growth and development cycle occurs without a period of dormancy.     

Activity and quantity of ribulose bisphosphate carboxylase-and phosphoenolpyruvate carboxylase-protein in two Crassulacean acid metabolism plants in relation to leaf age,nitrogen nutrition,and point in time during a day/night cycle

Activity of ribulose 1,5-bisphosphate (RuBP) carboxylase in leaf extracts of the constitutive Crassulacean acid metabolism (CAM) plant Kalanchoe pinnata (Lam.) Pers. decreased with increasing leaf age, whereas the activity of phosphoenolpyruvate (PEP) carboxylase increased. Changes in enzyme activities were associated with changes in the amount of enzyme proteins as determined by immunochemical analysis, sucrose density gradient centrifugation, and SDS gel electrophoresis of leaf extracts. Young developing leaves of plants which received high amounts of NO ₃ ^- during growth contained about 30% of the total soluble protein in the form of RuBP carboxylase; this value declined to about 17% in mature leaves. The level of PEP carboxylase in young leaves of plants at high NO ₃ ^- was an estimated 1% of the total soluble protein and increased to approximately 10% in mature leaves, which showed maximum capacity for dark CO₂ fixation. The growth of plants at low levels of NO ₃ ^- decreased the content of soluble protein per unit leaf area as well as the extractable activity and the percentage contribution of both RUBP carboxylase and PEP carboxylase to total soluble leaf protein. There was no definite change in the ratio of RuBP carboxylase to PEP carboxylase activity with a varying supply of NO ₃ ^- during growth. It has been suggested (e.g., Planta 144, 143–151, 1978) that a rhythmic pattern of synthesis and degradation of PEP carboxylase protein is involved in the regulation of -carboxylation during a day/night cycle in CAM. No such changes in the quantity of PEP carboxylase protein were observed in the leaves of Kalanchoe pinnata (Lam.) Pers. or in the leaves of the inducible CAM plant Mesembryanthemum crystallinum L.Abbreviations CAM Crassulacean acid metabolism - RuBP ribulose 1,5-bisphosphate - PEP phosphoenolpyruvate - G-6-P glucose-6-phosphate     

Photosynthesis and phage: early studies on phosphorus metabolism in photosynthetic microorganisms with 32P,and how they led to the serendipic discovery of 32P-decay suicide of bacteriophage

During my PhD thesis research (1946–1949), I explored the effects of light on the uptake of ³²P-labeled inorganic phosphate (P_i) by cells of photosynthetic bacteria and microalgae, and the dynamics of P turnover between low and high molecular weight cell constituents. The results were interpreted as evidence for the conversion of light energy to the chemical energy of phosphorylated compounds. The experimental results also suggested to me that the precursors of the P in DNA bacteriophages of Escherichia coli must be low molecular weight phosphorylated compounds present within the host cells and led to the design of an experiment to determine the conservation of ³²P of an infecting phage particle in its numerous progeny. The experiment envisaged was never conducted because phage labeled with ³²P of high specific activity showed unexpected loss of viability. Thus, by serendipity, ‘suicide’ of phage due to ³²P-β decay was discovered. ³²P-decay ‘suicide’ provided a technique that was useful for analysis of phage genetic structure and replication. This memoir describes the unusual circumstances leading to the decisive role of serendipity in revealing an extraordinary phenomenon. This revised version was published online in June 2006 with corrections to the Cover Date.