Genomic analysis of orthologous mouse and human olfactory receptor loci

Olfactory receptor (OR) genes represent ≈1% of genomic coding sequence in mammals, and these genes are clustered on multiple chromosomes in both the mouse and human genomes. We have taken a comparative genomics approach to identify features that may be involved in the dynamic evolution of this gene family and in the transcriptional control that results in a single OR gene expressed per olfactory neuron. We sequenced ≈350 kb of the murine P2 OR cluster and used synteny, gene linkage, and phylogenetic analysis to identify and sequence ≈111 kb of an orthologous cluster in the human genome. In total, 18 mouse and 8 human OR genes were identified, including 7 orthologs that appear to be functional in both species. Noncoding homology is evident between orthologs and generally is confined within the transcriptional unit. We find no evidence for common regulatory features shared among paralogs, and promoter regions generally do not contain strong promoter motifs. We discuss these observations, as well as OR clustering, in the context of evolutionary expansion and transcriptional regulation of OR repertoires.

Conditional Synergism between Cryptochrome 1 and Phytochrome B Is Shown by the Analysis of phyA, phyB, and hy4 Simple, Double, and Triple Mutants in Arabidopsis

Wild-type or phyA, phyB, or hy4 mutant Arabidopsis seedlings lacking phytochrome A (phyA), phytochrome B (phyB), or cryptochrome 1 (cry1), respectively, and the double and triple mutants were used in combination with blue-light treatments given simultaneously with red or far-red light. We investigated the interaction between phytochromes and cry1 in the control of hypocotyl growth and cotyledon unfolding. Under conditions deficient for cry1 (short exposures to blue light) or phyB (far-red background), these photoreceptors acted synergistically: Under short exposures to blue light (3 h/d) added to a red-light background, cry1 activity required phyB (e.g. the hy4 mutant was taller than the wild type but the phyBhy4 mutant was not taller than the phyB mutant). Under prolonged exposures to blue light (24 h/d) added to a far-red light background, phyB activity required cry1 (e.g. the phyAphyB mutant was taller than the phyA mutant but the phyAphyBhy4 mutant was not taller than the phyAhy4 mutant). Under more favorable light inputs, i.e. prolonged exposures to blue light added to a red-light background, the effects of cry1 and phyB were independent. Thus, the synergism between phyB and cry1 is conditional. The effect of cry1 was not reduced by the phyA mutation under any tested light condition. Under continuous blue light the triple mutant phyAphyBhy4 showed reduced hypocotyl growth inhibition and cotyledon unfolding compared with the phyAphyB mutant. The action of cry1 in the phyAphyB double mutant was higher under the red-light than the far-red-light background, indicating a synergistic interaction between cry1 and phytochromes C, D, or E; however, a residual action of cry1 independent of any phytochrome is likely to occur.

Analysis of Cell Division and Elongation Underlying the Developmental Acceleration of Root Growth in Arabidopsis thaliana1

To investigate the relation between cell division and expansion in the regulation of organ growth rate, we used Arabidopsis thaliana primary roots grown vertically at 20°C with an elongation rate that increased steadily during the first 14 d after germination. We measured spatial profiles of longitudinal velocity and cell length and calculated parameters of cell expansion and division, including rates of local cell production (cells mm−1 h−1) and cell division (cells cell−1 h−1). Data were obtained for the root cortex and also for the two types of epidermal cell, trichoblasts and atrichoblasts. Accelerating root elongation was caused by an increasingly longer growth zone, while maximal strain rates remained unchanged. The enlargement of the growth zone and, hence, the accelerating root elongation rate, were accompanied by a nearly proportionally increased cell production. This increased production was caused by increasingly numerous dividing cells, whereas their rates of division remained approximately constant. Additionally, the spatial profile of cell division rate was essentially constant. The meristem was longer than generally assumed, extending well into the region where cells elongated rapidly. In the two epidermal cell types, meristem length and cell division rate were both very similar to that of cortical cells, and differences in cell length between the two epidermal cell types originated at the apex of the meristem. These results highlight the importance of controlling the number of dividing cells, both to generate tissues with different cell lengths and to regulate the rate of organ enlargement.

Structural analysis of p185c-neu and epidermal growth factor receptor tyrosine kinases: oligomerization of kinase domains.

The epidermal growth factor receptor (EGFR) and p185c-neu proteins associate as dimers to create an efficient signaling assembly. Overexpression of these receptors together enhances their intrinsic kinase activity and concomitantly results in oncogenic cellular transformation. The ectodomain is able to stabilize the dimer, whereas the kinase domain mediates biological activity. Here we analyze potential interactions of the cytoplasmic kinase domains of the EGFR and p185c-neu tyrosine kinases by homology molecular modeling. This analysis indicates that kinase domains can associate as dimers and, based on intermolecular interaction calculations, that heterodimer formation is favored over homodimers. The study also predicts that the self-autophosphorylation sites located within the kinase domains are not likely to interfere with tyrosine kinase activity, but may regulate the selection of substrates, thereby modulating signal transduction. In addition, the models suggest that the kinase domains of EGFR and p185c-neu can undergo higher order aggregation such as the formation of tetramers. Formation of tetrameric complexes may explain some of the experimentally observed features of their ligand affinity and hetero-receptor internalization.

Lens complementation system for the genetic analysis of growth, differentiation, and apoptosis in vivo.

A genetic approach has been established that combines the advantages of blastocyst complementation with the experimental attributes of the developing lens for the functional analysis of genes governing cellular proliferation, terminal differentiation, and apoptosis. This lens complementation system (LCS) makes use of a mutant mouse strain, aphakia (ak), homozygotes of which fail to develop an ocular lens. We demonstrate that microinjection of wild-type embryonic stem (ES) cells into ak/ak blastocysts produces chimeras with normal ES-cell-derived lenses and that microinjection of Rb-/- ES cells generates an aberrant lens phenotype identical to that obtained through conventional gene targeting methodology. Our determination that a cell autonomous defect underlies the aphakia condition assures that lenses generated through LCS are necessarily ES-cell-derived. LCS provides for the rapid phenotypic analysis of loss-of-function mutations, circumvents the need for germ-line transmission of null alleles, and, most significantly, facilitates the study of essential genes whose inactivation is associated with early lethal phenotypes.

Development of a Household Pharmaceutical Waste Collection Program for Atlanta, Georgia: An Analysis of Risk Factors and Public Awareness with a Comprehensive Collection Plan

Decades of mixed messages from three federal agencies left many Americans unaware of the hazards associated with the indiscriminate disposal of unwanted or expired medicines. For this Capstone project, a systematic review of state and federal regulations was undertaken to determine how these laws obstruct household pharmaceutical waste collection. In addition, a survey of 654 Atlanta residents was conducted to evaluate unwanted medicine disposal habits, awareness of pharmaceutical compounds being detected in drinking water, surface, and ground waters, and willingness to participate in a household pharmaceutical waste collection program. Survey responses were tabulated to provide overall results and by age group, gender, and race. A household pharmaceutical waste collection plan was developed for the city and included as an appendix.

Analysis of internal astigmatism and higher order aberrations in eyes implanted with a new diffractive multifocal toric intraocular lens

Background To evaluate the intraocular lens (IOL) position by analyzing the postoperative axis of internal astigmatism as well as the higher-order aberration (HOA) profile after cataract surgery following the implantation of a diffractive multifocal toric IOL. Methods Prospective study including 51 eyes with corneal astigmatism of 1.25D or higher of 29 patients with ages ranging between 20 and 61 years old. All cases underwent uneventful cataract surgery with implantation of the AT LISA 909 M toric IOL (Zeiss). Visual, refractive and corneal topograpy changes were evaluated during a 12-month follow-up. In addition, the axis of internal astigmatism as well as ocular, corneal, and internal HOA (5-mm pupil) were evaluated postoperatively by means of an integrated aberrometer (OPD Scan II, Nidek). Results A significant improvement in uncorrected distance and near visual acuities (p < 0.01) was found, which was consistent with a significant correction of manifest astigmatism (p < 0.01). No significant changes were observed in corneal astigmatism (p = 0.32). With regard to IOL alignment, the difference between the axes of postoperative internal and preoperative corneal astigmatisms was close to perpendicularity (12 months, 87.16° ± 7.14), without significant changes during the first 6 months (p ≥ 0.46). Small but significant changes were detected afterwards (p = 0.01). Additionally, this angular difference correlated with the postoperative magnitude of manifest cylinder (r = 0.31, p = 0.03). Minimal contribution of intraocular optics to the global magnitude of HOA was observed. Conclusions The diffractive multifocal toric IOL evaluated is able to provide a predictable astigmatic correction with apparent excellent levels of optical quality during the first year after implantation.

Teachers’ beliefs about diversity: an analysis from a personal and professional perspective

The purpose of this study was to examine the beliefs that teachers have about diversity and their level of sensitivity towards some topics related to it. Moreover, beliefs were compared according to teachers’ personal and professional views and teaching experience. The Personal and Professional Beliefs about Diversity Scales (Pohan and Aguilar, 1999) were administered to a sample of 233 teachers. Results showed highly positive beliefs towards diversity in all its dimensions (cultural, linguistic and social diversity, ability, gender, sexual orientation and religion), especially regarding its personal implications compared to the professional ones. Likewise, it was observed a significant relationship between years of teaching experience and professional beliefs about diversity, so teachers with no school experience showed a higher tolerance than those with teaching experience, mainly in aspects related to cultural, linguistic and social differences, ability and gender. The implications that these results have for educational practice and the need for the development of multicultural education courses that favour an effective teaching are discussed.

Water polo throwing speed and body composition: an analysis by playing positions and opposition level

The aim of this study was to develop an anthropometric profile on highly skilled male water polo players by specific playing positions. Also, to identify significant relationships between these features an overhead throwing speed in highly skilled male Water Polo players by specific playing positions. Methods: A total of 94 male water polo players (24.5±5.3 yrs) who were playing in the Spanish King´s cup were studied. Subjects were grouped according to their specific playing positions: 15 goalkeepers, 45 offensive wings, 20 center backs and 14 center forwards. Anthropometric assessment was made following ISAK protocols. Hand grip and throwing speed in several situations were also assessed. A one-way analysis of variance (ANOVA) was used to determine if significant differences existed among the four playing positions. Pearson product-moment correlation coefficients (r) were used to determine the relationships of all anthropometric measures with throwing speed and hand grip. The total player’s somatotype was endomorphic-mesomorphic (2.9–5.8–2.3). Center forwards exhibit important anthropometric differences compared with the other specific playing positions in elite male water polo players, but no differences were found in throwing speed by specific playing positions in each throwing conditions. Moreover, a higher number of relationships between anthropometric and throwing speed were found in wings and also in center backs but no relationships were found in center forwards. The data reflects the importance of muscle mass and upper body in the throwing skill. Coaches can use this information in order to select players for the different specific positions.