Relationship between the level of estrone sulfate in the plasma and the number of fetuses during pregnancy in the gilt

Estrone sulfate was measured in the plasma of pregnant and nonpregnant gilts between Days 10 and 32 after estrus. Estrone sulfate was found to rise sharply in pregnant gilts beginning at Day 18 and to decline at Day 30 to Day 32. Estrone levels were not related to litter size. The level of estrone sulfate on Days 20, 22, 24 and 26 was significantly correlated with litter size at slaughter on Day 32. Reduction of the number of live fetuses by crushing them in utero at Day 40 or between Days 30 to 60 did not cause a subsequent reduction in the level of estrone sulfate, whereas reduction at Day 24 did cause a decline in estrone sulfate. The level of estrone sulfate in plasma of gilts at 20 to 28 days after mating was higher in pregnant than in nonpregnant gilts. The relative level of estrone sulfate would enable one to estimate litter size at Days 20 to 28 days but not later. Because of the limitations of the assay in exact quantitation of the levels of estrone sulfate, the results can only be considered qualitative.     

Antibodies to spiroperidol and their anti-idiotypes as probes for studying dopamine receptors

Spiroperidol was covalently conjugated to bovine serum albumin (BSA). Conjugated spiroperidol was almost as efficient as free spiroperidol in its binding capacity to dopamine receptor. Antibodies to spiroperidol were produced in rabbits following repeated immunizations with the conjugate of spiroperidol and BSA. The obtained antibodies have an apparent K_D of 0.02 nM for [³H]-spiroperidol. These antibodies bind also to other butyrophenones with IC₅₀ values three to four orders of magnitude higher than the IC₅₀ obtained with unlabeled spiroperidol. Antibodies were purified from anti-spiroperidol sera by affinity chromatography. Anti-idiotypic antibodies were raised in rabbits by immunization with the purified anti-spiroperidol antibodies. Some rabbits produced anti-idiotypic antibodies which bind to rat and calf striatum.     

Monoclonal antibodies modify acetylcholine-induced ionic channel properties in cultured chick myoballs

Summary Monoclonal antibodies directed against the cholinergic binding site of the acetylcholine receptor were found to alter the ion channel properties in cultured chick myoballs. Time and dose dependent reduction in acetylcholine sensitivity was observed. Noise analysis experiments indicated a decrease in the mean single channel conductance and an increase in the mean single channel open time.     

Reassociation of Purified Lipopolysaccharide and Phospholipid of the Bacterial Cell Envelope: Electron Microscopic and Monolayer Studies

Phosphatidyl ethanolamine and lipopolysaccharide were extracted and purified from the cell envelope fractions of Escherichia coli and Salmonella typhimurium. The two components were studied separately and after recombination, by use of electron microscopy and monolayer techniques, and by measuring their ability to participate in the enzyme-catalyzed uridine diphosphate-galactose:lipopolysaccharide alpha, 3 galactosyl transferase reaction, which requires a lipopolysaccharide-phospholipid complex as substrate. Electron microscopy of purified lipopolysaccharide showed a uniform population of hollow spheres, with each sphere bounded by a continuous leaflet. The diameter of the spheres was approximately 500 to 1,000 A, and the thickness of the enveloping leaflet was approximately 30 A. Phosphatidyl ethanolamine showed a regular lamellar structure. When lipopolysaccharide and phosphatidyl ethanolamine were mixed under conditions of heating and slow-cooling, the leaflet of the lipopolysaccharide spheroids appeared to extend directly into the phosphatidyl ethanolamine structure, with continuity between the two leaflets. Various stages of penetration were seen. At high concentrations of lipopolysaccharide, there were disruptive changes in phosphatidyl ethanolamine leaflets similar to those seen when saponin acts on cholesterol-lecithin leaflets. Monolayer experiments indicated that lipopolysaccharide penetrated a monomolecular film of phosphatidyl ethanolamine at an air-water interface, as revealed by an increase in surface pressure. The results indicate that a common leaflet structure containing lipopolysaccharide and phosphatidyl ethanolamine may be formed in vitro, and suggest that a similar leaflet may exist in the intact bacterial cell envelope.     

The effect of osmotic `shock'' on the swelling pattern and respiratory control of rat-liver mitochondria

1. Rat-liver mitochondria suspended in 0.25m-sucrose were exposed for a few seconds to strongly hypo-osmotic conditions, and then the osmolarity of the medium was raised again to 0.25 with the aid of tris chloride (osmotic ;shock'). 2. Mitochondria after hypo-osmotic pretreatment lost their capacity for slow energy-dependent swelling in iso-osmotic tris buffer and showed no respiratory control. 3. Swelling could be induced in the ;shocked' mitochondria by ATP but not by addition of respiratory substrates. 4. It was shown that cytochrome c is lost from ;shocked' mitochondria when they come into contact with the tris buffer present in the assay medium, and that the changes observed in the pattern of swelling, as well as in respiratory control, are directly connected with this loss of cytochrome c. 5. The results of the investigation are discussed with regard to the role of cytochrome c in swelling and respiratory control.     

Differential Effect of Polyamines on T4 Morphogenesis

The 5-fluorouracil (5 FU) technique for the phenotypic reversion of amber mutants was used to demonstrate that under certain circumstances, in the presence of putrescine or spermidine, early mutants have an enhanced response to 5 FU, whereas late mutants have a delayed response. Bacteria infected by T4D wild-type bacteriophage did not produce phage in the presence of high putrescine concentrations. Pulse treatments with putrescine showed that the production of lysozyme depends on a putrescine-sensitive process that begins immediately after infection at 26 C and ends at 36 min or even later. The addition of putrescine at any time during the critical period between 0 and 36 min led to a corresponding delay in lysozyme synthesis after the inhibitor was removed. Intracellular phage maturation was delayed by the addition of 100 mumoles of putrescine per ml. Early enzymes were not affected by the diamine, but the level of phage deoxyribonucleic acid was considerably decreased by the inhibitor. The putrescine-sensitive process that affects the timing of maturation is suggested to be the natural process controlling the T4 "clock."     

Relation between optical configuration and immunogenicity of synthetic polypeptides

1. Three random linear copolymers composed of two or three of the amino acids d-tyrosine, d-glutamic acid, d-alanine and d-lysine, and a branched multichain copolymer with a poly-d-lysine backbone and polymeric side chains of d-tyrosine and d-glutamic acid, were found to be non-antigenic in rabbits, by precipitin and passive cutaneous anaphylaxis, and in guinea pigs, by delayed hypersensitivity tests. The corresponding four copolymers of l-amino acids were shown to be antigenic by all the three criteria. 2. No immunological cross-reactions were observed between the polypeptides composed of d-amino acids and the corresponding l-amino acid copolymers. 3. Similarly, an azobenzenearsonic acid conjugate of poly-d-tyrosine was shown to be non-antigenic in guinea pigs, in contrast with an analogous conjugate of poly-l-tyrosine. Animals sensitized with the conjugate of poly-l-tyrosine did not exhibit delayed skin reactions, when cross-tested with the d-conjugate. 4. A linear polymer composed of d-tyrosine, l-glutamic acid and l-alanine was found to be immunogenic and to cross-react with the corresponding polymer composed exclusively of d-amino acids.     

Centromere-Linkage Analysis and Consolidation of the Zebrafish Genetic Map

The ease of isolating mutations in zebrafish will contribute to an understanding of a variety of processes common to all vertebrates. To facilitate genetic analysis of such mutations, we have identified DNA polymorphisms closely linked to each of the 25 centromeres of zebrafish, placed centromeres on the linkage map, increased the number of mapped PCR-based markers to 652, and consolidated the number of linkage groups to the number of chromosomes. This work makes possible centromere-linkage analysis, a novel, rapid method to assign mutations to a specific linkage group using half-tetrads.     

Does observed fertility maximize fitness among New Mexican men?

Our objective is to test an optimality model of human fertility that specifies the behavioral requirements for fitness maximization in order (a) to determine whether current behavior does maximize fitness and, if not, (b) to use the specific nature of the behavioral deviations from fitness maximization towards the development of models of evolved proximate mechanisms that may have maximized fitness in the past but lead to deviations under present conditions. To test the model we use data from a representative sample of 7,107 men living in Albuquerque, New Mexico, between 1990 and 1993. The model we test proposes that low fertility in modern settings maximizes number of grandchildren as a result of a trade-off between parental fertility and next generation fertility. Results do not show the optimization, although the data do reveal a trade-off between parental fertility and offspring education and income. We propose that two characteristics of modern economies have led to a period of sustained fertility reduction and to a corresponding lack of association between income and fertility. The first is the direct link between costs of investment and wage rates due to the forces of supply and demand for labor in competitive economies. The second is the increasing emphasis on cumulative knowledge, skills, and technologies in the production of resources. Together they produce historically novel conditions. These two features of modern economies may interact with evolved psychological and physiological mechanisms governing fertility and parental investment to produce behavior that maximizes the economic productivity of lineages at the expense of fitness. If cognitive processes evolved to track diminishing returns to parental investment and if physiological processes evolved to regulate fertility in response to nutritional state and patterns of breast feeding, we might expect non-adaptive responses when returns from parental investment do not diminish until extremely high levels are reached. With high economic payoffs from parental investment, people have begun to exercise cognitive regulation of fertility through contraception and family planning practices. Those cognitive processes maynot have evolved to handle fitness trade-offs between fertility and parental investment. A preliminary presentation of this data was published in R. I. M. Dunbar, ed.,Human Reproduction Decisions: Biological and Social Perspectives. New York: St. Martin’s Press, 1995. Support for the research project, “Male Fertility and Parenting in New Mexico,” began with two seed grants from the University of New Mexico’s Biomedical Research Grants Program, 1988 and 1989, and one from the University of New Mexico Research Allocations Committee, 1988. Further seed money as well as interim funding came from the William T. Grant Foundation (#89130589 and #91130501). The major support for the project came from the National Science Foundation from 1990 to 1993 (#BNS-9011723 and #DBS-911552). Both National Science Foundation grants included Research Experience for Undergraduates supplements. Hillard S. Kaplan is an Associate Professor of Anthropology at the University of New Mexico. His earlier research and publications focused on food sharing, time allocation, parental investment, and reproductive strategies among Ache hunter-gatherers in Paraguay, Machiguenga and Piro forager-horticulturalists in Peru, and villagers of several ethnicities in Botswana. New research and theory concern fertility, parental investment, and mating strategies in developed and developing nations. This research formulates a new theory of reproductive decision-making and the demographic transition, integrating human capital and parental investment theory in a synthesis of economic and evolutionary approaches. Jane B. Lancaster is a Professor of Anthropology at the University of New Mexico. Her research and publications are on human reproductive biology and behavior, especially human parental investment; women’s reproductive biology of pregnancy, lactation, and child-spacing; and male fertility and investment in children. Current research with Hillard S. Kaplan is on male life history strategies among a large sample of men in New Mexico. She has coedited three books on human parental investment:School-Age Pregnancy and Parenthood (with B. Hamburg),Parenting across the Life Span (with J. Altmann, A. Rossi, and L. Sherrod), andOffspring Abuse and Neglect (with R. Gelles). She is scientific editor of a quarterly journal,Human Nature: An Interdisciplinary, Biosocial Perspective published by Aldine de Gruyter. She is also a council member of the newly formed Human Behavior and Evolution Society. John A. Bock is Andrew W. Mellon Post-Doctoral Fellow in Epidemiology and Population Health at the National Centre for Epidemiology and Population Health, The Australian National University. His research focuses on the allocation of parental investment and the determinants of children’s activities, integrating aspects of economic and evolutionary theory. He has ongoing field research with Bantu and Bushmen agro-pastoralists and forager-horticulturalists in the Okavango Delta, Botswana. He is also collaborating with Lancaster and Kaplan on the determinants of progeny distribution and homosexuality among New Mexican men. Sara E. Johnson is a Ph.D. candidate at the University of New Mexico. Her major research trajectory focuses on trade-offs in life history characters. Her research experience includes participation in a study of variation in growth and development among children in a multi-ethnic community in the Okavango Delta, Botswana, in addition to her dissertation work on individual variation in growth and mortality among juvenile baboons. She is collaborating with Lancaster and Kaplan on the association between survival and fertility among Albuquerque men.