The Genetics, Pathology, and Molecular Biology of T-Cytoplasm Male Sterility in Maize

This chapter reviews the genetics, pathology, and molecular biology of T-cytoplasm male sterility in maize. The chapter discusses the role of cytoplasmic male sterility systems in facilitating the production of hybrid seeds. The effects of widespread planting of T-cytoplasm maize on the severe 1970 epidemic and effect of a mitochondria1 gene on disease susceptibility and male sterility are discussed. It also discusses the involvement of nuclear cytoplasmic interactions in restoration of cms-T, the perspectives of cms-T researchers, and future directions. In cms-T plants, male sterility is associated with premature breakdown of the mitochondria-rich, tapetal cell layer of the anther; this layer is crucial to pollen production because it supplies nutrients to the developing microspores. In many species, cms is associated with the expression of novel open-reading frames in the mitochondrial genome. The studies provided a foundation for further research that resulted in the cloning of the T-urf13 and Rf2 genes from maize and the ChPKSl gene from C. heterostrophus, and the generation of models for the topology of urf13 in the inner mitochondrial membrane, Rfl-mediated processing of T-urfl3 transcripts, and the evolution of toxin biosynthesis in C. heterostrophus and M. zeae-maydis

Quantitative analysis of epithelial cells in urine from men with and without urethritis: implications for studying epithelial: pathogen interactions in vivo

<p>Abstract</p> <p>Background</p> <p>Epithelial cells in first catch urine (FCU) specimens from 87 men with and without urethritis were quantified. Epithelial cells were broadly categorised into transitional and squamous populations using morphological characteristics and immunostaining with anti-pan leukocyte and anti-cytokeratin monoclonal antibodies.</p> <p>Findings</p> <p>The majority (77/87 = 89%) of samples contained both transitional (76/87 = 87%; range 1 × 10⁴– 6 × 10⁵, median 6 × 10⁴) and squamous (57/87 = 66%; range 1 × 10⁴– 8 × 10⁵, median 2 × 10⁴) epithelial cells. The number of transitional cells correlated with the number of squamous cells (Spearman's rho = 0.697 p < 0.001). Squamous, but not transitional, cell numbers correlated with leukocyte numbers (Spearman's rho = 0.216 p = 0.045 and rho = 0.171 and p = 0.113, respectively). However there was no significant difference in epithelial cell numbers between men with and without urethritis. Nevertheless, some men with urethritis had relatively high numbers of transitional cells in their FCU. Transitional cells were morphologically heterogeneous and appeared to display complex cytokeratin phenotypes.</p> <p>Conclusion</p> <p>Further studies are required to explore the complexity of epithelial cell populations in urine. These would provide novel opportunities for studying cellular interactions of <it>C. trachomatis </it>in male urethral infections, about which little is currently known.</p

The signal-to-noise analysis of the Little-Hopfield model revisited

Using the generating functional analysis an exact recursion relation is derived for the time evolution of the effective local field of the fully connected Little-Hopfield model. It is shown that, by leaving out the feedback correlations arising from earlier times in this effective dynamics, one precisely finds the recursion relations usually employed in the signal-to-noise approach. The consequences of this approximation as well as the physics behind it are discussed. In particular, it is pointed out why it is hard to notice the effects, especially for model parameters corresponding to retrieval. Numerical simulations confirm these findings. The signal-to-noise analysis is then extended to include all correlations, making it a full theory for dynamics at the level of the generating functional analysis. The results are applied to the frequently employed extremely diluted (a)symmetric architectures and to sequence processing networks.Comment: 26 pages, 3 figure

The X-ray Cluster Normalization of the Matter Power Spectrum

The number density of galaxy clusters provides tight statistical constraints on the matter fluctuation power spectrum normalization, traditionally phrased in terms of sigma_8, the root mean square mass fluctuation in spheres with radius 8 h^-1 Mpc. We present constraints on sigma_8 and the total matter density Omega_m0 from local cluster counts as a function of X-ray temperature, taking care to incorporate and minimize systematic errors that plagued previous work with this method. In particular, we present new determinations of the cluster luminosity - temperature and mass - temperature relations, including their intrinsic scatter, and a determination of the Jenkins mass function parameters for the same mass definition as the mass - temperature calibration. Marginalizing over the 12 uninteresting parameters associated with this method, we find that the local cluster temperature function implies sigma_8 (Omega_m0/0.32)^alpha = 0.86+/-0.04 with alpha = 0.30 (0.41) for Omega_m0 < 0.32 (Omega_mo > 0.32) (68% confidence for two parameters). This result agrees with a wide range of recent independent determinations, and we find no evidence of any additional sources of systematic error for the X-ray cluster temperature function determination of the matter power spectrum normalization. The joint WMAP5 + cluster constraints are: Omega_m0 = 0.30+0.03/-0.02 and sigma_8 = 0.85+0.04/-0.02 (68% confidence for two parameters).Comment: 31 pages, 16 figures, accept for publication in ApJ 609, Jan. 10, 200

The effect of an intervention to improve newly qualified teachers’ interpersonal style, students motivation and psychological need satisfaction in sport-based physical education

Recent developments in self-determination theory research in the educational setting (e.g., Reeve, Deci, & Ryan, 2004), suggest that teachers’ interpersonal style should be considered as consisting of three dimensions: autonomy-support, structure and interpersonal involvement. Based on this theoretical proposition, the purpose of the present study was to test the effects of a training program for three physical education newly qualified teachers on the aforementioned teachers’ overt behaviors and students’ psychological needs satisfaction, self-determined motivation and engagement in sport-based physical education. After a baseline period of four lessons, the teachers attended an informational session on adaptive student motivation and how to support it. The training program also included individualized guidance during the last four lessons of the cycle. Results revealed that from pre- to post-intervention: (1) teachers managed to improve their teaching style in terms of all three dimensions, and (2) students were receptive to these changes, as shown by increases in their reported need satisfaction, self-determined motivation and engagement in the class

Virtual Lab Demonstrations Improve Students’ Mastery of Basic Biology Laboratory Techniques

Biology laboratory classes are designed to teach concepts and techniques through experiential learning. Students who have never performed a technique must be guided through the process, which is often difficult to standardize across multiple lab sections. Visual demonstration of laboratory procedures is a key element in teaching pedagogy. The main goals of the study were to create videos explaining and demonstrating a variety of lab techniques that would serve as teaching tools for undergraduate and graduate lab courses and to assess the impact of these videos on student learning. Demonstrations of individual laboratory procedures were videotaped and then edited with iMovie. Narration for the videos was edited with Audacity. Undergraduate students were surveyed anonymously prior to and following screening to assess the impact of the videos on student lab performance by completion of two Participant Perception Indicator surveys. A total of 203 and 171 students completed the pre- and posttesting surveys, respectively. Statistical analyses were performed to compare student perceptions of knowledge of, confidence in, and experience with the lab techniques before and after viewing the videos. Eleven demonstrations were recorded. Chi-square analysis revealed a significant increase in the number of students reporting increased knowledge of, confidence in, and experience with the lab techniques after viewing the videos. Incorporation of instructional videos as prelaboratory exercises has the potential to standardize techniques and to promote successful experimental outcomes

High Plasmid Gene Protein 3 (Pgp3) Chlamydia trachomatis Seropositivity, Pelvic Inflammatory Disease, and Infertility Among Women, National Health and Nutrition Examination Survey, United States, 2013-2016

BACKGROUND. Chlamydia trachomatis causes pelvic inflammatory disease (PID) and tubal infertility. Plasmid gene protein 3 antibody (Pgp3Ab) detects prior chlamydial infections. We evaluated for an association of high chlamydial seropositivity with sequelae using a Pgp3Ab multiplex bead array (Pgp3AbMBA). METHODS. We performed chlamydia Pgp3AbMBA on sera from women 18–39 years old participating in the 2013–2016 National Health and Nutrition Examination Survey (NHANES) with urine chlamydia nucleic acid amplification test results. High chlamydial seropositivity was defined as a median fluorescence intensity (MFI ≥ 50 000; low-positive was MFI > 551–<50 000. Weighted US population high-positive, low-positive, and negative Pgp3Ab chlamydia seroprevalence and 95% confidence intervals (CI) were compared for women with chlamydial infection, self-reported PID, and infertility. RESULTS. Of 2339 women aged 18–39 years, 1725 (73.7%) had sera, and 1425 were sexually experienced. Overall, 104 women had high positive Pgp3Ab (5.4% [95% CI 4.0–7.0] of US women); 407 had lowpositive Pgp3Ab (25.1% [95% CI 21.5–29.0]), and 914 had negative Pgp3Ab (69.5% [95% CI 65.5–73.4]). Among women with high Pgp3Ab, infertility prevalence was 2.0 (95% CI 1.1–3.7) times higher than among Pgp3Ab-negative women (19.6% [95% CI 10.5–31.7] versus 9.9% [95% CI 7.7–12.4]). For women with low Pgp3Ab, PID prevalence was 7.9% (95% CI 4.6–12.6) compared to 2.3% (95% CI 1.4–3.6) in negative Pgp3Ab. CONCLUSIONS. High chlamydial Pgp3Ab seropositivity was associated with infertility although small sample size limited evaluation of an association of high seropositivity with PID. In infertile women, Pgp3Ab may be a marker of prior chlamydial infection