Showing papers by "Rockefeller University published in 1982"

Isolation of intracellular membranes by means of sodium carbonate treatment: application to endoplasmic reticulum.

Abstract: A rapid and simple method for the isolation of membranes from subcellular organelles is described. The procedure consists of diluting the organelles in ice-cold 100 mM Na2CO3 followed by centrifugation to pellet the membranes. Closed vesicles are converted to open membrane sheets, and content proteins and peripheral membrane proteins are released in soluble form. Here we document the method by applying it to various subfractions of a rat liver microsomal fraction, prepared by continuous density gradient centrifugation according to Beaufay et al. (1974, J. Cell Biol. 61:213-231). The results confirm and extend those of previous investigators on the distribution of enzymes and proteins among the membranes of the smooth and rough endoplasmic reticulum. In the accompanying paper (1982, J. Cell Biol. 93:103-110) the procedure is applied to peroxisomes and mitochondria.

Signal recognition particle contains a 7S RNA essential for protein translocation across the endoplasmic reticulum.

Abstract: In addition to its previously characterized, six different polypeptide components, signal recognition protein--which functions in protein translocation across and integration into the endoplasmic reticulum membrane--contains a 7S RNA molecule. The RNA is closely identified with the small cytoplasmic 7SL RNA and is required for both structural and functional properties of signal recognition protein--which we therefore rename signal recognition particle.

Variety in the level of gene control in eukaryotic cells

Abstract: In light of present progress in the understanding of how messenger RNA is constructed in eukaryotic cells, the levels of gene control are discussed. Transcriptional control, assessed by the rate of synthesis of specific nuclear RNA, is strongly indicated to be the most frequent level of control. Definition of eukaryotic transcription units as simple (encoding one protein} and complex (encoding two or more proteins) affords a framework in which to discuss control at the level of RNA processing for which several examples also are known. Finally, differential stability of cytoplasmic mRNAs and differential translation, both well established, are briefly described.

Supersymmetry, Cosmology, and New Physics at Teraelectronvolt Energies

Abstract: If one assumes a spontaneously broken local supersymmetry, big-bang cosmology implies that the universe is filled with a gravitino (${g}_{\frac{3}{2}}$) gas---possibly its dominant constituent. From the observational bound on the cosmological mass density it follows that ${m}_{{g}_{\frac{3}{2}}}\ensuremath{\lesssim}1$ keV. Correspondingly, the supersymmetry breaking parameter $F$ satisfies $\sqrt{F}\ensuremath{\lesssim}2\ifmmode\times\else\texttimes\fi{}{10}^{3}$ TeV, requiring new supersymmetric physics in the teraelectronvolt energy region. An exact sum rule is derived and used to estimate the threshold and cross section for the production of the new states.

Connections of vocal control nuclei in the canary telencephalon.

Abstract: Connections of two telencephalic vocal control nuclei, the hyperstriatum ventrale, pars caudale (HVc), and robust nucleus of the archistriatum (RA), were investigated in adult canaries. Methods used were transport of horseradish peroxidase and 3H-adenosine and silver staining of degenerating axons. Three nuclei project to HVc: medial nucleus magnocellularis ofthe anterior neostriatum (MAN), nucleus interfacialis (NIf) of midneostriatum, and nucleus uvaeformis (Uva) of the diecephalon. Uva also projects to NIf. NIf and Uva have not been described previously. HVc projects to area X of lobus parolfactorius, to RA, and to field Avalanche of hyperstriatum ventrale. Nucleus RA receives projections from HVc and from lateral MAN. All these projections are ipsilateral. No gross male/female differences were apparent in the projections to and from HVc. Uptake of HRP by cell somata in HVc following localized injections of this substance into RA or HVc suggests that HVc is composed of rostrocaudally organized clusters of cells, with little lateral communication between them.

The central projections of the trigeminal, facial, glossopharyngeal and vagus nerves: an autoradiographic study in the rat.

Abstract: The central distributions of primary afferent axons in the facial, trigeminal (mandibular branch), glossopharyngeal, and vagal nerves of the rat have been re-examined using the autoradiographic tracing technique after injections of [3H]proline or [3H]leucine into their peripheral ganglia. Within the nucleus of the solitary tract (NST), the labeled terminals from VII, V, IX and X form a continuous distribution that spans the length of this nucleus. Sensory axons in VII terminate mainly within the lateral division of the rostral NST, although some of the terminals extend further caudally within the nucleus. Immediately caudal to the rostral NST, the distribution continues with major contributions from V and IX. Both are confined mainly to the lateral division of the NST, although some of the fibers in IX terminate within the medial division. Injections into the inferior ganglion of X confirm the extensive distribution of vagal axons as they ramify significantly within the lateral division, and virtually monopolize the medial division of the NST. Thus, the major zone of convergency for these 4 cranial nerves is the lateral division of the nucleus from the level of the entering fascicles of IX caudally to the level of the area postrema. Furthermore, only X has a crossed projection as vagal axons invade the commissural nucleus and the medial division of the contralateral NST. Vagal fibers also enter the area postrema bilaterally. Finally, some afferent fibers from VII, IX and X descend in the dorsal part of the spinal trigeminal tract and terminate within the marginal subdivision of the spinal trigeminal nucleus pars caudalis, as well as the dorsal horn of the cervical spinal cord.

Fast atom bombardment study of glycerol: mass spectra and radiation chemistry

Abstract: Neat glycerol was irradiated with beam of Ar atoms and ions produced by a Capillaritron gun operated at 5 KeV. The FAB spectrum produced changed markedly as the irradiation continued. Studies were made with irradiations lasting 12 minutes and 35 minutes. Both the absolute and relative intensities of the ions in the glycerol spectrum change, and new ions are formed. The glycerol sample after the irradiation contains clear crystals. The irradiated sample was subjected to negative chemical ionization analysis, which provided further evidence for the formation of radiation products from the glycerol and also evidence about the identities of the products. The major new products formed are

Polypeptide and phospholipid composition of the membrane of rat liver peroxisomes: comparison with endoplasmic reticulum and mitochondrial membranes.

Abstract: Membranes were isolated from highly purified peroxisomes, mitochondria, and rough and smooth microsomes of rat liver by the one-step Na2CO3 procedure described in the accompanying paper (1982, J. Cell Biol. 93:97-102). The polypeptide compositions of these membranes were determined by SDS PAGE and found to be greatly dissimilar. The peroxisomal membrane contains 12% of the peroxisomal protein and consists of three major polypeptides (21,700, 67,700 and 69,700 daltons) as well as some minor polypeptides. The major peroxisomal membrane proteins as well as most of the minor ones are absent from the endoplasmic reticulum (ER). Conversely, most ER proteins are absent from peroxisomes. By electron microscopy, purified peroxisomal membranes are approximately 6.8 nm thick and have a typical trilaminar appearance. The phospholipid/protein ratio of peroxisomal membranes is approximately 200 nmol/mg; the principal phospholipids are phosphatidyl choline and phosphatidyl ethanolamine as in ER and mitochondrial membranes. In contrast to the mitochondria, peroxisomal membranes contain no cardiolipin. All the membranes investigated contain a polypeptide band with a molecular mass of approximately 15,000 daltons. Whether this represents an exceptional common membrane protein or a coincidence is unknown. The implications of these results for the biogenesis of peroxisomes are discussed.

Developmental overproduction and selective attrition: New processes in the epigenesis of birdsong

Abstract: All phases of song development from infancy to adulthood were studied intensively in a group of laboratory-reared birds. Male swamp sparrows, Melospiza georgiana, trained with tape-recorded songs in infancy, developed song some 8 months later, averaging 2.2 song types per bird. Analysis of the intermediate stage of plastic song revealed that the birds generated 4 to 5 times more song material than was needed for the species-specific song repertoire. The excess was discarded at the time of full song crystallization. Indications that the attrition process is selective include tendencies to retain imitated rather than nonimitated elements, and the rejection of heterospecific elements. Attrition may also be influenced by vocal stimulation at the time of song crystallization, providing an opportunity for behavioral adjustment even though new themes can no longer be learned. Attrition has been described in the transition in human infants from babbling to speech.

Abnormal oxidative metabolism of estradiol in women with breast cancer.

Abstract: The three dominant oxidative biotransformations of estradiol were examined in 10 normal women and 33 females with breast cancer by using a recently devised radiometric method. Estradiol tracers, labeled with 3H specifically in the 17 alpha, C-2, or 16 alpha position, were used to measure both the rate and extent of 17 beta-ol oxidation (the initial metabolic step) and the subsequent 2- and 16 alpha-oxidative reactions. The mean +/- SEM values for the extent of extradiol metabolism at these three specific sites for the extent of estradiol metabolism at these three specific sites were 76.9 +/- 5.3%, 31.1 +/- 4.0%, and 9.3 +/- 0.8%, respectively in normal subjects. Corresponding data in patients with breast cancer--i.e., 73.0 +/- 4.2%, 32.7 +/- 2.7%, and 14.9 +/- 1.5%--revealed a significantly greater extent of 16 alpha-hydroxylation in the latter population. Because the 16 alpha-hydroxylated compounds (including estriol) are themselves potent estrogens, these changes may have important hyperestrogenic consequences that could have a bearing on the etiology of the disease.

Walls bounded by strings

Abstract: Extended structures consisting of walls bounded by strings appear in some unified gauge theories. The Spin(10) grand-unified-theory model provides the simplest example, provided the symmetry breaking proceeds via SU(4)\ifmmode\times\else\texttimes\fi{}SU(2)\ifmmode\times\else\texttimes\fi{}SU(2). It is shown that the presence of such structures may cause conflict with standard cosmology.

Recognition of Individuals Within and Between Groups of Free-Ranging Vervet Monkeys1

Abstract: SYNOPSIS. The ability of animals to recognize and classify others reflects the selective pressures acting on individuals within a particular social framework. Data on recognition therefore allow us to consider social structure from the animal's point of view. Here we review data on recognition within groups of free-ranging vervet monkeys, and present evidence of recognition across groups. Within groups, experiments suggest that animals may proceed beyond simple discriminations of kin and non-kin to create a taxonomy in which group members are both distinguished as individuals and grouped into higher order units, apparently on the basis of matrilineal kinship. Across groups, observation indicates that male transfer is non-random, and that the exchange of males between groups is correlated with reduced aggression. Playback experiments demonstrate that monkeys associate the vocalizations of particular individuals with particular groups. We conclude that the social organization of vervet monkeys is best regarded as a “community” of groups, within which individuals recognize each other and share a high degree of genetic relatedness despite the maintenance of otherwise discrete social units.

Inhibition of experimental ascending urinary tract infection by an epithelial cell-surface receptor analogue

Abstract: It has been shown that the establishment of urinary tract infection by Escherichia coli is dependent on attachment of the bacteria to epithelial cells. The attachment involves specific epithelial cell receptors, which have been characterized as glycolipids. Reversible binding to cell-surface mannosides may also be important. This suggests an approach to the treatment of infections--that of blocking bacterial attachment with cell membrane receptor analogues. Using E. coli mutants lacking one or other of the two binding specificities (glycolipid and mannose), we show here that glycolipid analogues can block in vitro adhesion and in vivo urinary tract infection.

The luteinizing hormone‐releasing hormone pathways in rhesus (Macaca mulatta) and pigtailed (Macaca nemestrina) monkeys: New observations on thick, unembedded sections

Abstract: Immunocytochemical procedures on thick, unembedded tissue sections were used to study the localization of LHRH neurons and fibers in the diencephalon and mesencephalon of rhesus and pigtailed macaques. Cell bodies were visualized in large numbers. Much of their dendritic arborization was also filled with reaction product. Cell bodies were present in the preoptic area, the periventricular hypothalamic zone from the level of the anterior hypothalamus to the premammillary nuclei, the infundibular nucleus, supraoptic nucleus, several septal nuclei, the nervus terminalis, and the amygdala. The localization of LHRH cells in several of these areas represents new observations. LHRH axons were observed to innervate the portal vessels in the median eminence, the organum vasculosum of the lamina terminalis, the median eminence, the organum vasculosum of the lamina terminalis, the medial mammillary nuclei, the epithalamus, and the amygdala. These observations are discussed in relationship to the regulation of gonadotropin secretion in the primate.

Steroid hormones: humoral signals which alter brain cell properties and functions.

Abstract: Publisher Summary The steroid hormones influence the brain to affect behavior. This chapter discusses the intracellular steroid receptors in neural tissue; their anatomical distribution and properties, their role in carrying hormone to the cell nucleus, and their effects upon gene expression. It also describes the direct effects of steroids upon neural tissue which do not appear to be mediated by intracellular steroid receptors. It provides a more integrated picture of how steroid hormones influence patterns of behavior during the development and in adult life, using as an example the effects of estradiol in the rat brain. The brain contains receptor sites for all five classes of steroid hormones. Brain regions that contain such cytosol steroid receptors also display translocation of labeled hormone to the cell nuclear compartment, and this phenomenon underlies autoradiographic localization of steroid hormone concentrating cells, because the presence of label over the cell nucleus provides a visually striking and quantifiable endpoint. Cell nuclear translocation of steroid hormones in neural tissues is not necessarily accompanied by the extensive cytosol receptor depletion even when nuclear sites are loaded to capacity. There are other, indirect demonstrations of genomic involvement in steroid action in the brain.

The evolutionary effects of mate selection

Abstract: Sexual selection is the subset of natural selection that depends on differential success in obtaining mates. Differential mating success within one sex, say males, may depend on the preferences of females for certain males, on the outcome of male-male competition for females, or on some combination of both processes. The purpose of this review is to analyze the evolutionary consequences of that component of sexual selection due to mating preferences. The most important step in such an analysis is to determine which characteristics of one sex determine mating preferences in the other sex, since these characteristics will be favored by sexual selection. In the past there has been much debate over the importance of mate choice as a selection pressure, and, in fact, about whether mate choice occurs at all (32, 63, 82, 128). This controversy can perhaps be largely avoided if mate choice is clearly defined. For the purposes of this review, mate choice includes all instances where there is differential mating success in one sex due to preferences exhibited by the other sex. Under this definition, mate choice includes preferences based on characters conferring genetic benefit to the young, on phenotypic characters conferring a more immediate benefit to the chooser (such as assistance with parental care), or even on characters external to the chosen individual (such as resources it controls).

Phagocytosis of Microorganisms

Abstract: For its survival, the host depends on an elaborate internal defense system to protect against persistent invasion by pathogenic microorganisms. This system is composed primarily of cellular and humoral components of the circulatory system and includes the "professional" phagocytes (polymorphonuclear leukocytes, monocytes, and tissue macrophages), antibody, and complement. The humoral component is often able to deal with invaders singlehandedly, as by antibody-independent or antibody-dependent complement lysis. However, the cellular and humoral components must cooperate to destroy better-equipped pathogens by the process of phagocytosis. Hundreds of studies on phagocytosis of one or another microorganism have been published. Experimental conditions in these studies have varied widely. Investigators have employed a variety of white cell types (polymorphonuclear leukocytes, monocytes, or macrophages) from different anatomical regions (usually blood, peritoneum, or alveoli) of different animals (often human, rabbit, guinea pig, or mouse). These white cells have been obtained in their resident state or after elicitation

Neural cell adhesion molecule is on embryonic muscle cells and mediates adhesion to nerve cells in vitro

Abstract: The interaction of nerves with muscles, particularly at neuromuscular junctions, is one of the most extensively studied areas of neurophysiology. From the point of view of developmental biology, however, little is known about the cellular and molecular events that lead to formation of these junctions1,2. In previous investigations of cell-cell adhesion in the chick embryo, we identified a molecule on the surface of essentially all nerve cells, called neural cell adhesion molecule (N-CAM)3,4, that appears to be a ligand in the formation of cell-cell bonds5. N-CAM is involved in a variety of developmental processes including neurite fasciculation and the formation of plexiform and cell layers in retinal tissue6–8. We report here that N-CAM antigenic determinants are also present on chick embryo skeletal muscle cells. This observation raised the possibility that N-CAM is involved in adhesion between nerve and muscle cells. In model systems set up to explore this possibility, we observed that myoblasts will adhere in vitro to nerve cells from retina, and that this adhesion can be inhibited by F(ab′) fragments of antibodies against N-CAM. In addition, membrane vesicles obtained from chick embryo brain or artificial vesicles5 reconstituted from lipid and affinity-purified N-CAM9 bound to the surface of myoblasts and myotubes; this binding was also blocked by anti-N-CAM F(ab′). These results suggest that the N-CAM adhesion system can facilitate nerve-muscle as well as nerve-nerve interactions in vitro.

Sex differences in rat brain oestrogen and progestin receptors.

Abstract: The brains of both male and female rats possess specific cytoplasmic receptors for oestrogens and progestins1, and it has been suggested that sex differences in the neuroendocrine and behavioural responses to these hormones result from differences in the number of steroid receptors in specific locations in the brain2. Although there have been numerous comparisons of steroid receptors in male and female brains3–9, the question of whether there are sex differences in these receptor systems remains unresolved, due in part to the inability of available biochemical techniques to achieve sufficiently high anatomical resolution. We have overcome this problem by applying the Palkovits punch-out technique10 to measure steroid receptors in hypothalamic nuclei known to be involved in behavioural and neuroendocrine control. We report here that castrated male rats have fewer oestrogen and progestin receptors in certain hypothalamic nuclei than females. This suggests that the relative insensitivity of male rats to feminine actions of gonadal steroids might be due in part to a lack of receptors for these steroids in highly localized brain regions.

Conserved charges from self-duality

Abstract: Given a simple self-dual quantum Hamiltonian $H=KB+\ensuremath{\Gamma}\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{B}$, where $K$ and $\ensuremath{\Gamma}$ are coupling constants, and the condition that $[B,[B,[B,\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{B}]]]=16[B,\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{B}]$, then we construct an infinite set of conserved charges ${Q}_{2n}$; $[H,{Q}_{2n}]=0$. In simple models, like the two-dimensional Ising or Baxter eight-vertex, these charges appear in the associated quantum theories and are equivalent to those which result from the transfer-matrix formulation and exact quantum integrability of the system. The power of our result is that it is an operator statement and does not refer to the number of dimensions or the nature of the space-time manifold: lattice, continuum, or loop space. It is suggested how the establishment of this link between duality and integrability could be used to exploit the Kramers-Wannier-type self-duality of the four-dimensional $\mathrm{SU}(N)$ gauge theory to find hidden symmetry.