The endocrinology of puberty and reproductive functioning in female cotton-top tamarins (Saguinus oedipus) under varying social conditions

Sexual maturation and fertility were assessed in fourteen cotton-top tamarin (Saguinus oedipus) females under various social conditions. Six tamarin females (20-28 mo of age) showed a suppression of fertility while living with their families. Hormonal profiles demonstrated low, acyclic levels of urinary luteinizing hormone (LH) and estrone-conjugates (E1C). A rapid onset of ovarian and pituitary cyclicity occurred when four of the six females were removed from their families and paired with an unrelated male. In one female, an ovulatory LH peak occurred as early as eight days after pairing and resulted in conception and full-term pregnancy. Two of the six females were housed in total isolation for 30 days following their removal from the family and prior to pairing. Gradual increases in hormone concentrations occurred during isolation; however, there was no ovarian cyclicity until each female was paired with an unrelated male. In all six females, conception occurred before or as a result of the third ovulatory cycle. Partial isolation of a 36-mo-old female resulted in elevated LH and E1C levels, but cyclicity was not observed until the female was paired with an unrelated male. These findings indicate that removal of a female from the family alone does not initiate ovarian cycling. Sexual maturation, or puberty, occurs in female tamarins living with their families between 15 and 17 mo of age when mean LH and E1C levels began to increase. However, when a female is removed and paired at 9 mo of age with an unrelated male, elevated levels of LH and E1C may be seen by 10 and 11 mo of age. Our findings indicate that a suppression of fertility occurs in cotton-top tamarins living with their families, but that reproductive suppression does not affect the process of sexual maturation. Both removal from the family environment and stimulation by an unrelated male tamarin were necessary to induce normal reproductive activity. An acceleration of puberty occurred when a female tamarin was removed from her family early in development and paired with a male.     

Transformation of NIH 3T3 fibroblasts by an activated form of p59hck.

Phosphorylation of a tyrosine residue near the carboxy terminus of src-family protein tyrosine kinases is believed to regulate the biological activity of these gene products. Conversion of this tyrosine in p59hck (Tyr-501) to a phenylalanine residue by using oligonucleotide-directed mutagenesis yielded a product (p59hckF501) with very potent transforming activity. Quantitative analysis by a soft-agar cloning assay revealed that p59hckF501 was more than 100-fold more effective than a closely related transforming element, p56lckF505, in colony formation. Cells bearing p59hckF501 had increased levels of protein phosphotyrosine. The ability of p59hckF501 to transform NIH 3T3 cells was abolished by a second mutation believed to destroy the ATP-binding domain.     

Biological effects of synthetic AKH in Manduca sexta and estimates of the amount of AKH in corpora cardiaca

Dose-response curves were measured with synthetic Manduca adipokinetic hormone (AKH) for glycogen phosphorylase activation in larvae and for lipid mobilization in adults. Both responses are known hormonal functions in Manduca sexta. In ligated larvae, full activation of glycogen phosphorylase was achieved with 0.1 pmol and half-maximal activation with 0.03-0.04 pmol. Maximal lipid mobilization in adults required 10 pmol and half-maximal mobilization 0.15 to 0.2 pmol, respectively. An estimate of AKH content of corpora cardiaca from M. sexta was gained by comparing the dose-response curves for synthetic Manduca AKH with curves from gland extracts. Corpora cardiaca extracts were also quantitated by high performance liquid chromatography. According to both estimates corpora cardiaca of adults contain 10-20 pmol AKH per pair, while a pair of larval corpora cardiaca contains 0.7-2 pmol.     

Temperature effects on malic-acid efflux from the vacuoles and on the carboxylation pathways in crassulacean-acid-metabolism plants

The studies described in the paper were conducted with tissue slices of Crassulacean acid metabolism (CAM) plants floating in isotonic buffer. In a first series of experiments, temperature effects on the efflux of [¹⁴C]malate and¹⁴CO₂ were studied. An increase of temperature increased the efflux from the tissue in a non-linear manner. The efflux was markedly influenced also by the temperatures applied during the pretreatment. The rates of label export in response to the temperature and the relative contributions of¹⁴CO₂ and [¹⁴C]malate to the label export were different in the two studied CAM plants (Kalanchoë daigremontiana, Sempervivum montanum). In further experiments, temperature response of the labelling patterns produced by¹⁴CO₂ fixation and light and darkness were studied. In tissue which had accumulated malate (acidified state) an increase of temperature decreased the rates of dark CO₂ fixation whilst the rates of CO₂ fixation in light remained largely unaffected. An increase of temperature shifted the labelling patterns from a C₄-type (malate being the mainly labelled compound) into a C₃-type (label in carbohydrates). No such shift in the labelling patterns could be observed in the tissue which had depleted the previously stored malate (deacidified state). The results indicate that in the acidified tissue the increase of temperature increases the efflux of malate from the vacuole by changing the properties of the tonoplast. It is assumed that the increased export of malic acid lowers the in-vivo activity of phosphoenol pyruvate carboxylase by feedback inhibition.Abbreviations CAM Crassulacean acid metabolism - FW fresh weight - PEPCase phosphoenolpyruvate carboxylase Dedicated to Professor O.L. Lange, Würzburg, on the occasion of his 60th birthday     

Inhibition of lipopolysaccharide activation of 7OZ/3 cells by anti-lipopolysaccharide antibodies

We have investigated the ability of mAb against LPS to inhibit LPS-induced activation of 7OZ/3 pre-B cells. The fine specificity and relative affinity of these mAb for lipid A and LPS were also determined. We found that antibodies inhibited only the activity of glycolipids which they bound with relatively high affinity. However, two high affinity antibodies binding to non-lipid A epitopes did not block cellular activation. Some, but not all, relatively high affinity antibodies binding to the lipid A region of the LPS molecule inhibited biologic activity. The inhibitory antibodies bound to at least two distinct epitopes within the lipid A region. These data suggest that LPS interacts with 7OZ/3 cells in a highly specific fashion.     

Partition coefficients of plant cuticles for monoterpenes

Summary Cuticle/water partition coefficients (K_c/w) for d-limonene, -pinene and -pinene were determined by an extrapolation and a desorption method. The sorption experiments were carried out with isolated angiosperm and gymnosperm cuticles and with [¹⁴C]-labelled monoterpenes, which were obtained biosynthetically. Both methods were suitable for the determination of the K_c/w of volatile hydrophobic compounds. For the angiosperm cuticles the partition coefficients are of the order of 10⁴, which indicates a high accumulation of monoterpenes in the cuticle. The values of the conifer cuticles of Picea abies (L.) Karst. and Abies alba Mill., however, are lower due to their high lignin content. This is proved by the increase of the partition coefficients after removal of polar and phenolic components. The K_c/w can be estimated with good accuracy from the octanol/water partition coefficient, which was determined experimentally.     

Immobilization of microsomes into alginate beads is a convenient method for producing glucuronides from drugs

Summary The production of glucuronides from drugs by immobilized microsomal uridine diphosphate (UDP)-glucuronosyltransferase has been investigated. Of all the immobilization methods used (covalent binding, adsorption by ionic or hydrophobic interactions), only entrapment of microsomes into alginate beads in the presence of polyethyleneimine was effective in producing high glucuronidation rates, thus leading to the formation of large amounts of metabolites. The performance of the bioreactor was optimized with the drug 3-azido-3-deoxythymidine (AZT), active against the human immunodeficiency virus, as a model substrate of UDP-glucuronosyltransferase. Calcium (12 mm) could optimally improve the stability of microsomes entrapped in alginate beads. Upon immobilization, enzyme activation occurred, leading to a fivefold increase in specific activity. The determination of apparent K _m and V _max revealed that AZT was a better substrate for the immobilized enzyme than free microsomes. The AZT-glucuronide production obtained after 6 h was threefold higher than that observed with free microsomes. This bioreactor was also efficient in production of glucuronides from structurally different compounds such as bilirubin, 4-nitrophenol, clofibric acid, pirprofen, dextrorphan or morphine, the corresponding glucuronide of which possesses pharmacological or toxicological interest. Offprint requests to: J. Magdalou     

Characterization of the glycosylation sites in yeast external invertase. I. N-linked oligosaccharide content of the individual sequons

External invertase is the product of the SUC2 gene of Saccharomyces cerevisiae. The deduced sequence of this enzyme (Taussig, R., and Carlson, M. (1983) Nucleic Acid Res. 11, 1943-1954) reveals it to contain 14 potential N-linked glycosylation sites, or sequons, although only 9-10 appear to be glycosylated (Trimble, R. B., and Maley, F. (1977) J. Biol. Chem. 252, 4409-4412). To determine the location of the glycosylated sequons, external invertase was deglycosylated with endo-beta-acetylglucosaminidase H and its component peptides analyzed by both fast atom bombardment mass spectrometry (FABMS) and classical peptide isolation procedures. By use of the former technique most of the glucosamine-containing sequons could be located and by the latter sufficient amounts of small glucosamine-containing peptides were isolated to enable their quantitation. From the combined FABMS and glucosamine analyses, it was established that eight of the sequons in a subunit of invertase are either completely or almost completely glycosylated, while five others are glycosylated to the extent of about 50% or less. In the case of two overlapping sequons (4 and 5), which include Asn92-Asn93-Thr-Ser, only the first Asn was glycosylated. Thus, all but one of the sequons of external invertase are glycosylated to some extent, giving an appearance of only 9-10 N-linked oligosaccharides/subunit. The sequence identity of both external and internal invertase was verified by FABMS and by peptide sequence analysis. In only one site was an amino acid found to differ from that deduced from the DNA sequence of the SUC2 gene. This occurred at position 390 where a proline was found in place of alanine, which could result from a single base change in the triplet specifying the latter amino acid.     

Technique for hand-rearing and reintroducing rejected cotton-top tamarin infants

During a one year period, seven rejected cotton-top tamarin infants were hand-reared. A hand-rearing program was developed which included the use of heated surrogates, a non-human primate infant formula, special nipples, and a systematic reintroduction into a family group. This regimen was quite successful. The hand-rearing process yielded a success rate of 75.0%, while the reintroduction process had a success rate of 80.0% for reintroduction into a family group and 100.0% survival rate.     

Amino acid sequence of Manduca sexta adipokinetic hormone elucidated by combined fast atom bombardment (FAB)/tandem mass spectrometry

Combination of Fast Atom Bombardment Tandem Mass Spectrometry with Amino Acid Analysis assigns the amino acid sequence of the Manduca sexta adipokinetic hormone as pGlu-Leu-Thr-Phe-Thr-Ser-Ser-Trp-GlyNH2. Similarities and differences with other invertebrate hormones and with mammalian glucagon are discussed.