Evolutionary novelties.

How novel traits arise in organisms has long been a major problem in biology. Indeed, the sharpest critiques of Darwin's theory of evolution by natural selection often centered on explaining how novel body parts arose. In his response to The Origin of Species, St.

Positive homotropic allosteric receptors for neutral guests: annulated tetrathiafulvalene-calix[4]pyrroles as colorimetric chemosensors for nitroaromatic explosives.

The study of positive homotropic allosterism in supramolecular receptors is important for elucidating design strategies that can lead to increased sensitivity in various molecular recognition applications. In this work, the cooperative relationship between tetrathiafulvalene (TTF)-calix[4]pyrroles and several nitroaromatic guests is examined. The design and synthesis of new annulated TTF-calix[4]pyrrole receptors with the goal of rigidifying the system to accommodate better nitroaromatic guests is outlined.

Quinobis(imidazolylidene): synthesis and study of an electron-configurable bis(N-heterocyclic carbene) and its bimetallic complexes.

Reaction of bromanil with N,N'-dimesitylformamidine followed by deprotonation with NaN(SiMe(3))(2) afforded 1,1',3,3'-tetramesitylquinobis(imidazolylidene) (1), a bis(N-heterocyclic carbene) (NHC) with two NHC moieties connected by a redox active p-quinone residue, in 72 % yield of isolated compound. Bimetallic complexes of 1 were prepared by coupling to FcN(3) (2) or FcNCS (3; Fc=ferrocenyl) or coordination to [M(cod)Cl] (4 a or 4 b, where M=Rh or Ir, respectively; cod=1,5-cyclooctadiene). Treatment of 4 a and 4 b with excess CO(g) afforded the corresponding [M(CO)(2)Cl] complexes 5 a and 5 b, respectively.

HoxA-11 and FOXO1A cooperate to regulate decidual prolactin expression: towards inferring the core transcriptional regulators of decidual genes.

During the menstrual cycle, the ovarian steroid hormones estrogen and progesterone control a dramatic transcriptional reprogramming of endometrial stromal cells (ESCs) leading to a receptive state for blastocyst implantation and the establishment of pregnancy. A key marker gene of this decidualization process is the prolactin gene. Several transcriptional regulators have been identified that are essential for decidualization of ESCs, including the Hox genes HoxA-10 and HoxA-11, and the forkhead box gene FOXO1A.

Metalloporphycenes: synthesis and characterization of (pentamethylcyclopentadienyl)ruthenium sitting-atop and pi-complexes.

Unprecedented porphycene complexes, containing a [RuCp*] (Cp*: pentamethylcyclopentadienyl) fragment accommodated in the central N(4) core or directly bonded to the "pi-face" of the macrocycle have been prepared and fully characterized, including via single crystal X-ray diffraction analysis. The optical and electrochemical properties of these new families of compounds were examined in detail, revealing fluorescence in the case of the "sitting-atop" complexes for which the lifetime was determined. For both metal (M = Cu, Ni) porphycene derivatives with a "fused" ruthenocene moiety, strong electronic communication was observed through efficient photoinduced electron transfer from the ruthenocene unit to the macrocycle after laser flash photolysis, affording a charge-separated state.

Pattern-based recognition for the rapid determination of identity, concentration, and enantiomeric excess of subtly different threo diols.

A pattern-based recognition approach for the rapid determination of the identity, concentration, and enantiomeric excess of chiral vicinal diols, specifically threo diols, has been developed. A diverse enantioselective sensor array was generated using three chiral boronic acid receptors and three pH indicators. The optical response produced by the sensor array was analyzed by two pattern-recognition algorithms: principal component analysis and artificial neural networks.

Did egg-laying boas break Dollo's law? Phylogenetic evidence for reversal to oviparity in sand boas (Eryx: Boidae).

Re-evolution of lost complex morphological characters has been proposed for several characters, including insect wings, limbs, eyes in snakes, and digits in lizards, among others. There has also been much interest in whether the transition from oviparity to viviparity is reversible, particularly in squamate reptiles where the transition to viviparity has occurred more times than in any other lineage. Here, we present a phylogenetic analysis of boid snakes based on a concatenated multigene study of all genera of erycines, New and Old World boines, plus other groups thought to be closely related with boines such as monotypic species Calabaria and Casarea.

"Wurster-type" ureas as redox-active receptors for anions.

Four redox-active receptors, 1-4, based on the incorporation of p-phenylenediamine(s) within a urea framework, were synthesized, and the affinities of two for a series of anions were quantified through UV-vis and NMR spectroscopic studies. The structure of 1 was confirmed by X-ray crystallography. For the oxoanions studied, complex stabilities approached 10(6) M(-1) in acetonitrile and decreased with the decreasing basicity of the anion (CH(3)COO(-) > C(6)H(5)COO(-) > H(2)PO(4)(-) > NO(2)(-) > NO(3)(-)).

Live-birth in vipers (Viperidae) is a key innovation and adaptation to global cooling during the Cenozoic.

The identification of adaptations and key innovations has long interested biologists because they confer on organisms the ability to exploit previously unavailable ecological resources and respond to novel selective pressures. Although it can be extremely difficult to test for the effects of a character on the rate of lineage diversification, the convergent evolution of a character in multiple lineages provides an excellent opportunity to test for the effect of that character on lineage diversification. Here, I examine the effect of parity mode on the diversification of vipers, which have independently evolved viviparity in at least 13 lineages.

Use with caution: developmental systems divergence and potential pitfalls of animal models.

Transgenic animal models have played an important role in elucidating gene functions and the molecular basis development, physiology, behavior, and pathogenesis. Transgenic models have been so successful that they have become a standard tool in molecular genetics and biomedical studies and are being used to fulfill one of the main goals of the post-genomic era: to assign functions to each gene in the genome. However, the assumption that gene functions and genetic systems are conserved between models and humans is taken for granted, often in spite of evidence that gene functions and networks diverge during evolution.

Bimetallic N-heterocyclic carbene-iridium complexes: investigating metal-metal and metal-ligand communication via electrochemistry and phosphorescence spectroscopy.

Bimetallic [Ir(COD)Cl] and [Ir(ppy)(2)] (COD = 1,5-cyclooctadiene; ppy = 2-phenylpyridyl) complexes bridged by 1,7-dimethyl-3,5-diphenylbenzobis(imidazolylidene) (1), in addition to their monometallic analogues supported by 1-methyl-3-phenylbenzimidazolylidene (2), were synthesized and studied. Electrochemical analyses indicated that 1 facilitated moderate electronic coupling between [Ir(COD)Cl] units (DeltaE = approximately 60 mV), but not [Ir(ppy)(2)]. The metal-based oxidation potentials for the bimetallic complexes were within 20 mV of those for their monometallic analogues.

A chloride-anion insensitive colorimetric chemosensor for trinitrobenzene and picric acid.

A new receptor, the bisTTF-calix[2]thiophene[2]pyrrole derivative 3, has been prepared from the Lewis acid-catalyzed condensation of 2,5-bis(1-hydroxymethylethyl)thiopheno-TTF and pyrrole. This new system is found to form complexes with the electron-deficient guests, trinitrobenzene (TNB) and picric acid (PA), which serve as models for nitroaromatic explosives. The binding phenomenon, which has been studied in organic solution using proton nuclear magnetic resonance and absorption spectroscopies, results in an easy-to-visualize color change in chloroform that is independent of the presence of chloride anion, a known interferant for an earlier tetrakisTTF-calix[4]pyrrole TNB chemosensor.

Probing intramolecular B-N interactions in ortho-aminomethyl arylboronic acids.

This work investigates the interplay between the intramolecular B-N dative bonding and solvent insertion in various ortho-methylamino arylboronic acids in protic media. (11)B NMR experiments were conducted to study the effect that the degree of substitution of the amine group has on B-N bonding versus solvent insertion. It was found that there is a slight increase in the amount of B-N dative bonding on going from a tertiary to a secondary to a primary amine group, but that solvent insertion dominates in all cases of the boronate esters.

Real-time determination of chloride anion concentration in aqueous-DMSO using a pyrrole-strapped calixpyrrole anion receptor.

The use of a pyrrole-strapped calix[4]pyrrole () permits the determination of chloride anion concentrations in mixed aqueous DMSO-d(6)-H(2)O environments via proton NMR spectroscopy.

Multiple chromosomal rearrangements structured the ancestral vertebrate Hox-bearing protochromosomes.

While the proposal that large-scale genome expansions occurred early in vertebrate evolution is widely accepted, the exact mechanisms of the expansion--such as a single or multiple rounds of whole genome duplication, bloc chromosome duplications, large-scale individual gene duplications, or some combination of these--is unclear. Gene families with a single invertebrate member but four vertebrate members, such as the Hox clusters, provided early support for Ohno's hypothesis that two rounds of genome duplication (the 2R-model) occurred in the stem lineage of extant vertebrates. However, despite extensive study, the duplication history of the Hox clusters has remained unclear, calling into question its usefulness in resolving the role of large-scale gene or genome duplications in early vertebrates.

Measuring transcription factor-binding site turnover: a maximum likelihood approach using phylogenies.

A major mode of gene expression evolution is based on changes in cis-regulatory elements (CREs) whose function critically depends on the presence of transcription factor-binding sites (TFBS). Because CREs experience extensive TFBS turnover even with conserved function, alignment-based studies of CRE sequence evolution are limited to very closely related species. Here, we propose an alternative approach based on a stochastic model of TFBS turnover.

Tetrathiafulvalene porphyrins.

Four tetrathiafulvalene (TTF)-annulated porphyrins 1-4 were synthesized and characterized. All contain a tetraphenylporphyrin (TPP) core onto which four, two, or one TTF subunits were annulated. Absorption and fluorescence spectroscopic studies together with electrochemical investigations reveal that interactions between the porphyrin system and the annulated TTF units take place in solution.

Rapid enantiomeric excess and concentration determination using simple racemic metal complexes.

Racemic-metal complexes were used to determine identity, enantiomeric excess, and concentration of chiral diamines using metal-to-ligand charge transfer bands in circular dichroism spectroscopy. It takes under just 2 min per sample to determine [G]t and %R with tolerable errors (19% and 4%, respectively). The simplicity of the achiral receptors employed confers to this technique great potential for high-throughput screening.

A molecular footprint of limb loss: sequence variation of the autopodial identity gene Hoxa-13.

The homeobox gene Hoxa-13 codes for a transcription factor involved in multiple functions, including body axis and hand/foot development in tetrapods. In this study we investigate whether the loss of one function (e.g.

Adaptive changes in the transcription factor HoxA-11 are essential for the evolution of pregnancy in mammals.

Evolutionary change in gene regulation can result from changes in cis-regulatory elements, leading to differences in the temporal and spatial expression of genes or in the coding region of transcription factors leading to novel functions or both. Although there is a growing body of evidence supporting the importance of cis-regulatory evolution, examples of protein-mediated evolution of novel developmental pathways have not been demonstrated. Here, we investigate the evolution of prolactin (PRL) expression in endometrial cells, which is essential for placentation/pregnancy in eutherian mammals and is a direct regulatory target of the transcription factor HoxA-11.

Crown-6-calix[4]arene-capped calix[4]pyrrole: an ion-pair receptor for solvent-separated CsF ions.

An ion-pair receptor, 1, containing both cation- and anion-recognizing sites, has been synthesized and characterized. Single-crystal X-ray diffraction structural studies and (1)H NMR spectroscopic analyses confirmed that 1 forms stable 1:1 complexes with CsF in solution and in the solid state in spite of the large separation enforced between the receptor-bound anion and cation. In 9:1 CDCl3/CD3OD, binding of fluoride anion within the calix[4]pyrrole core of 1 was not observed in the absence of a cobound cesium cation; however, it was seen in this solvent mixture under conditions where a Cs(+) cation was bound to the crown ether-strapped calix[4]arene subunit.

Using enantioselective indicator displacement assays to determine the enantiomeric excess of alpha-amino acids.

Enantioselective indicator displacement assays (eIDAs) were used for the determination of enantiomeric excess (ee) of alpha-amino acids as an alternative to the labor-intensive technique of chromatography. In this study, eIDAs were implemented by the use of two chiral receptors [(Cu(II)(1)](2+), [Cu(II)(2)](2+)) in conjunction with the indicator chrome azurol S. The two receptors were able to enantioselectively discriminate 13 of the 17 analyzed alpha-amino acids.

Binuclear organometallic ruthenium complexes of a Schiff base expanded porphyrin.

The synthesis of binuclear organometallic ruthenium complexes of an expanded porphyrin-type macrocycle is reported; pyrrolic hydrogen bonding donors were found to interact with ancillary ligands in the primary coordination sphere and to stabilize coordinated dioxygen in an eta(2)-fashion.

A new bismuth iron oxyphosphate,Bi6(Bi0.32Fe0.68)(PO4)4O4.

Iron was inserted into the known crystal structure of the bismuth phosphate oxide Bi(6.67)(PO(4))(4)O(4) to ascertain its location in the vacancies associated with the bismuth ion located at the origin of the unit cell. Single-crystal X-ray diffraction refinements converged to a model of composition Bi(6)(Bi(0.