Synthesis of 11-cis-locked bicyclo[5.1.0]octanyl retinal and an enantioselective binding to bovine opsin

Both enantiomers of 13-(E) and 13-(Z) isomers of 11-cis-locked bicyclo[5.1.0]octanyl retinal were prepared by an improved synthesis and incubated with bovine opsin. The synthesis also establishes the absolute configuration of the enantiomers. Only one of the enantiomers binds to opsin, thus showing the steric restrictions regarding the middle polyene moiety of the retinoid molecule; this is in sharp contrast to the known leniency of the ring moiety binding site of retinoids. However, although one enantiomer is incorporated into the pigment, the circular dichroic spectrum of the pigment incorporating the bound enantiomer yields only a very weak Cotton effect, showing that, once incorporated, the bicyclo[5.1.0]octanyl chromophore is flattened by the opsin binding site. The titled retinoid was synthesized for study of the absolute conformation of the retinal pigment in rhodopsin.     

Molecular size of the 5-HT3 receptor solubilized from NCB 20 cells.

The 5-HT3 hydroxytryptamine receptor from NCB 20 cells was solubilized and the molecular and hydrodynamic properties of the receptor were investigated. The receptor was identified by binding of the radioligand 3-NN'-[3H]dimethyl-8-azabicyclo[3.2.1]octanyl indol-3-yl carboxylate ester [( 3H]Q ICS 205-930) to NCB 20 membranes (Bmax = 1.19 +/- 0.31 pmol/mg of protein; Kd = 0.43 +/- 0.076 nM) and was optimally solubilized with 0.5% deoxycholate. [3H]Q ICS 205-930 labelled one population of sites in solution (Bmax = 1.11 +/- 0.4 pmol/mg of protein; Kd = 0.48 +/- 0.06 nM; n = 4). The characteristics of [3H]Q ICS 205-930 binding were essentially unchanged by solubilization, and competition for [3H]Q ICS 205-930 binding by a series of 5-HT3 agonists and antagonists was consistent with binding to a 5-HT3 receptor site and was similar to that observed for 5-HT3 receptors solubilized from rat brain [McKernan, Quirk, Jackson & Ragan (1990) J. Neurochem. 54, 924-930]. Some physical properties of the solubilized receptor were investigated. The molecular size (Stokes radius) of the [3H]Q ICS 205-930-binding site was measured by gel-exclusion chromatography in a buffer containing 0.2% Lubrol and 0.5 M-NaCl and was determined as 4.81 +/- 0.15 nm (mean +/- S.E.M.; n = 6). Sucrose-density-gradient centrifugation was also performed under the same detergent and salt conditions to determine the partial specific volume (v) of the detergent-receptor site complex. This was found to be 0.794 ml.g-1. Sucrose-density-gradient centrifugation was carried out in both 1H2O and 2H2O to allow correction for detergent binding to the receptor. The Mr of the 5-HT3 receptor under these conditions was calculated as 249,000 +/- 18,000 (n = 3). The size and physical properties of the 5-HT3 receptor are similar to those observed for members of the family of ligand-gated ion channels.     

Ophryogleua hypertrophica n.sp. (Giliata Hymenostomatida)

Ophryoglena hypertrophica is distinguished by its tomites and its pyriform theronts; by its elliptical and flattened macronucleus with 2 or 3 coupled micronuclei; by its large trophont; by its tomont covered with a thin mucous layer at the interior of which are formed 4 or 8 tomites closely bound one to another. Its physiological evolution is characteristic; the tomite when it comes out of the tomont undergoes a secondary encystment and then becomes the theront. Sometimes the tomite is rostrated and is not attracted by the tissues; the tomite undergoes as before a secondary encystment, but divides inside the cyst. This type also produces complete or partial particular palintomies and regularly forms resistant cysts.     

High-frequency P element loss in Drosophila is homolog dependent

P transposable elements in Drosophila melanogaster can undergo precise loss at a rate exceeding 13% per generation. The process is similar to gene conversion in its requirement for a homolog that is wild type at the insertion site and in its reduced frequency when pairing between the homologs is inhibited. However, it differs from classical gene conversion by its high frequency, its requirement for P transposase, its unidirectionality, and its occurrence in somatic and premeiotic cells. Our results suggest a model of P element transposition in which jumps occur by a "cut-and-paste" mechanism but are followed by double-strand gap repair to restore the P element at the donor site. The results also suggest a technique for site-directed mutagenesis in Drosophila.     

Focal adhesion kinase regulation of N-WASP subcellular localization and function

N-WASP is a member of the WASP family of proteins that regulate actin cytoskeleton remodeling. FAK is a cytoplasmic tyrosine kinase implicated in integrin signaling during cell migration. Here we identify a direct interaction between N-WASP and FAK and show that N-WASP is phosphorylated by FAK at a conserved tyrosine residue, Tyr(256). We found that phosphorylation of Tyr(256) affected N-WASP nuclear localization, suggesting that phosphorylation of N-WASP by FAK may regulate its activity in vivo by altering its subcellular localization. We also showed that the nuclear localization of N-WASP is dependent on its being in the open conformation either after its activation by Cdc42 or the truncation of the C-terminal VCA domain. Phosphorylation of Tyr(256) of N-WASP could reduce its interaction with nuclear importin NPI-1, which might be responsible for its decreased nuclear localization. Lastly, we show that phosphorylation of Tyr(256) plays an important role in promoting cell migration. Together, these results suggest a novel regulatory mechanism of N-WASP by tyrosine phosphorylation and subcellular localization and its potential role in the regulation of cell migration.     

Mucopolysaccharide Which Regulates Growth in Neurospora

Neurospora produces a mucopolysaccharide (called MP) which inhibits its growth, causes vacuolation and agglutination of its cells, and precipitates its purified membrane protein. Cultures of a colonial strain display a phase of slow growth; the induction of this phase is traced to the production of MP by the mold. Stationary-phase cultures of wild type also produce MP. MP is a polymer of galactosamine, its amino groups only partially acetylated, probably containing other minor components. MP molecular weight is approximately 10(6). Complete acetylation abolishes the biological activities of MP. It is suggested that the regulatory effect of MP is mediated by its interaction with the protoplasmic membrane.     

The N-terminal fragment of Reelin is generated after endocytosis and released through the pathway regulated by Rab11

Reelin is a large secreted glycoprotein essential for brain formation, but its trafficking and function at the molecular level remain incompletely understood. After binding to its receptor, Reelin is internalized by endocytosis. Here we show that internalized Reelin is subject to specific proteolysis within the cell and its N-terminal fragment is re-secreted. This re-secretion is inhibited by bafilomycin A₁ or by expression of a mutant of Rab11, a regulator of the recycling pathway. As the N-terminal fragment does not bind to Reelin receptor but has homology to F-spondin, its recycling may be involved in the regulation of extracellular matrix.     

Male‐female differences in family size preferences among college students

Abstract

Three dimensions of isolated spousal separation largely determine its fertility impact: (1) length, (2) “completeness” (degree to which it is eliminating fecundability during fecundable months), and (3) its timing as defined by the reproductive state of the wife at its start. While it is obvious that by starting when the wife is in the fecundable state its net delaying of next conception is maximized, it is much less clear with which reproductive state its start should coincide in order to minimize its fertility impact. By means of a simple model, it is shown that for minimum impact a separation should start later in a pregnancy the longer is post‐partum anovulation, the higher is the level of intrauterine mortality, and the shorter is the period of separation. Conditions of natural fertility are assumed.     

Construction of proteolysis resistant human interleukin-2 by fusion to its protective single chain antibody

Interleukin-2 (IL-2) is a 15 kDa cytokine secreted by T-cells. Consequence to its natural function as locally secreted short-term messenger, its half-life in circulation is short and provided mainly by fast renal clearance due to its low molecular weight and its proteolytic susceptibility. These are common characteristics for most cytokines, resulting in low clinical utility. In this study we report the construction of an IL-2 fusion-protein comprising a protective anti-hIL-2 single chain antibody that was selected from a phage display library and the hIL-2. This IL-2 fusion-protein is fully human and resistant to inactivation by the ubiquitous lysosomal protease-cathepsin D, which is implicated in the in vivo inactivation of IL-2. In contrast, the native IL-2 lost practically all of its activity under these conditions. This resistance is due to the interaction of the single chain domain with its epitope on IL-2 thus masking possible cleavage sites. We suggest that this 45 kDa proteolysis resistant IL-2 fusion-protein upon further increase of its molecular weight by common fusion techniques to at least 75 kDa will exhibit significantly longer half-life in vivo and a higher clinical utility than either the native IL-2 or any of its reported long T/2 derivatives.     

Detection of HBs antigen by hemagglutination inhibition tests; experiment with standardization]

The standarization of a reagent for automated detection of HBs antigen by an inhibition of the hemagglutination reaction is described. Its advantages are its specificity, its fast efficiency, its low cost. But, its handling is delicate and requires a good technicity.     

Characterization of the Aerial Escape Response of the African Butterfly Fish, Pantodon buchholzi Peters

We studied the startle response of the African butterfly fish, Pantodon buchholzi (Osteoglossomorpha, Osteoglossoidea). It is an upward movement, mediated by abduction of the pectoral fins, and is elicited by mechanical and visual stimuli. Because this fish inhabits the first few centimeters beneath the water surface, its startle response results in an aerial excursion that may be described as ballistic-like, following a motion as defined by linear acceleration. We show that the aerial excursion is well-modeled by a parabola. On average, a fish jumps no more than twice its height and travels horizontally about five times its standard length. The fish may exhibit variable in-flight trunk and fin movements, but neither increases the travel distance in air following the initial in-water propulsive event. Similar vertical jumps also occur entirely within the water column suggesting that this motor behavior of Pantodon is a general escape behavior analogous to a Mauthner neuron-induced escape response. The variability in its posture in air and its direction of motion after reentering the water enhances this act of vertical flight as a step in this fish's escape behavior. The aerial aspect of its escape behavior is only a consequence of its position in the water column.     

The Role of the Principle of Object-relatedness in the Theory of Activity

The present state of the theory of activity (by which we mean the concept developed by Leont'ev and his school) undoubtedly deserves serious discussion. Such a discussion must not be reduced, as often happens, to a critique of this theory by representatives of other schools and currents in psychology that are based on different theoretical positions (i.e., to a criticism from without), on the one hand, or to an unconditional acceptance of all of its postulates by proponents of this theory, on the other. In my view, the kind of critique of this theory that is most relevant and acutely necessary in terms of both its prospects of development and the extent to which its perceptions accord with other psychological currents is of another sort, namely, a critique from within, by which I mean analysis of its own laws, of the internal logic of development of the theory, and of its internal contradictions, which define its present status and the dynamics of its development. Such an analysis should enable us to stimulate more effectively the internal mechanism of development and self-development of the theory of activity and ensure a transition from a period of stagnation that has produced nothing of note to a progressive evolution of its content and its explanatory power.     

A simple electrostatic criterion for predicting the thermal stability of proteins

The enhancement of protein thermostability is an important issue for both basic science and biotechnology purposes. We have developed a thermostability criterion for a protein in terms of a quasi-electric dipole moment (contributed by its charged residues) defined for an electric charge distribution whose total charge is not zero. It was found that minimization of the modulus of this dipole moment increased its thermal stability, as demonstrated by surveying these values in pairs of mesostable-thermostable homologous proteins and in mutations described in the literature. The analysis of these observations provides criteria for thermostabilization of a protein, by computing its dipole profile. This profile is obtained by direct substitution of each amino acid of the sequence by either a positive, negative or neutral amino acid, followed by a recalculation of the dipole moment. As an experimental example, these criteria were applied to a beta-glucanase to enhance its thermal stability.     

Epidermal growth factor: structure, location, phosphorylation and regulation of its receptor

Epidermal growth factor (EGF) is a Mr 6045 polypeptide first characterized for its ability to stimulate mitogenesis in epidermal and epithelial cells. The first step in the action of the growth factor is its binding to specific, high affinity membrane receptors. These receptors have been studied in a number of tissues and cell culture lines. The level of EGF receptors is modulated by many agents. EGF down-regulates its receptor. In addition, the number of EGF receptors is decreased by other growth factors (platelet-derived growth factor; transforming growth factor), by many tumor promoters and by viral transformation. Several hormones also can regulate EGF binding in its target tissues.     

Test reduction: I--Introduction and review of published work.

The word "test" is used in a more general sense to describe the process of eliciting evidence of any kind from a patient, and this paper explores the thesis that much evidence is unnecessary and that therefore much test reduction is possible. The value of test reduction can be measured by its efficiency--that is, its effect on the misclassification of disease--or, preferably, by some measure of its cost-effectiveness.     

Endothelin-1 as a neuropeptide: neurotransmitter or neurovascular effects?

Endothelin-1 (ET-1) is an endothelium-derived peptide that also possesses potent mitogenic activity. There is also a suggestion the ET-1 is a neuropeptide, based mainly on its histological identification in both the central and peripheral nervous system in a number of species, including man. A neuropeptide role for ET-1 is supported by studies showing a variety of effects caused following its administration into different regions of the brain and by application to peripheral nerves. In addition there are studies proposing that ET-1 is implicated in a number of neural circuits where its transmitter affects range from a role in pain and temperature control to its action on the hypothalamo-neurosecretory system. While the effect of ET-1 on nerve tissue is beyond doubt, its action on nerve blood flow is often ignored. Here, we review data generated in a number of species and using a variety of experimental models. Studies range from those showing the distribution of ET-1 and its receptors in nerve tissue to those describing numerous neurally-mediated effects of ET-1.     

Proctolin: a potent inhibitor of aminoenkephalinase

Proctolin is a potent selective inhibitor of aminoenkephalinase. The specificity of its inhibition of various aminopeptidases is similar to that of puromycin; it inhibits aminoenkephalinase, but not leucine aminopeptidase or aminopeptidase M. Enkephalin breakdown by synaptic plasma membrane, but not by brain slices, is sensitive to proctolin. The inhibition by proctolin is partially caused by its resistance to enzymatic breakdown. The inhibition is of mixed type and is concentration dependent, and the two amino acids at the N-terminal are important for its action. The minimal structure for inhibition is a dipeptide with a basic amino acid at the N-terminal and a basic or an aromatic amino acid at the C-terminal.     

Oligomerization and Phosphorylation Dependent Regulation of ArgBP2 Adaptive Capabilities and Associated Functions

ArgBP2 (Arg-Binding Protein 2/SORBS2) is an adaptor protein involved in cytoskeleton associated signal transduction, thereby regulating cell migration and adhesion. These features are associated with its antitumoral role in pancreatic cancer cells. Tyrosine phosphorylation of ArgBP2, mediated by c-Abl kinase and counterbalanced by PTP-PEST phosphatase, regulates many of its interactions. However, the exact mechanisms of action and of regulation of ArgBP2 remain largely unknown. We found that ArgBP2 has the capacity to form oligomers which are destabilized by tyrosine phosphorylation. We could show that ArgBP2 oligomerization involves the binding of one of its SH3 domains to a specific proline rich cluster. ArgBP2 self-association increases its binding to some of its molecular partners and decreased its affinity for others. Hence, the phosphorylation/oligomerization state of ArgBP2 directly regulates its functions by modulating its adaptive capabilities. Importantly, using a human pancreatic cancer cell model (MiaPaCa-2 cells), we could validate that this property of ArgBP2 is critical for its cytoskeleton associated functions. In conclusions, we describe a new mechanism of regulation of ArgBP2 where tyrosine phosphorylation of the protein interfere with a SH3 mediated self-interaction, thereby controlling its panel of interacting partners and related functions.     

中国兰科植物三个新记录种

报道了中国兰科植物的三个新记录种,裂唇卷瓣兰(Bulbophyllum picturatum),长柄虾脊兰(Calan-the allizettei)和绿花毛兰(Eria lanigera)。裂唇卷瓣兰的中萼片全缘前部具一粒状附属物,唇瓣基部两侧具耳。长柄虾脊兰的中裂片非常小并具三条褶片。黄花毛兰的花黄绿色,唇瓣不裂。