High-Resolution,Non-Invasive Imaging of Upper Vocal Tract Articulators Compatible with Human Brain Recordings

A complete neurobiological understanding of speech motor control requires determination of the relationship between simultaneously recorded neural activity and the kinematics of the lips, jaw, tongue, and larynx. Many speech articulators are internal to the vocal tract, and therefore simultaneously tracking the kinematics of all articulators is nontrivial—especially in the context of human electrophysiology recordings. Here, we describe a noninvasive, multi-modal imaging system to monitor vocal tract kinematics, demonstrate this system in six speakers during production of nine American English vowels, and provide new analysis of such data. Classification and regression analysis revealed considerable variability in the articulator-to-acoustic relationship across speakers. Non-negative matrix factorization extracted basis sets capturing vocal tract shapes allowing for higher vowel classification accuracy than traditional methods. Statistical speech synthesis generated speech from vocal tract measurements, and we demonstrate perceptual identification. We demonstrate the capacity to predict lip kinematics from ventral sensorimotor cortical activity. These results demonstrate a multi-modal system to non-invasively monitor articulator kinematics during speech production, describe novel analytic methods for relating kinematic data to speech acoustics, and provide the first decoding of speech kinematics from electrocorticography. These advances will be critical for understanding the cortical basis of speech production and the creation of vocal prosthetics.     

Immunochemical characterization and localization of nitrate reductase in norflurazon-treated soybean cotyledons

Immunochemical procedures were used to characterize and localize NADH:nitrate reductase (NR; EC 1.6.6.1) in cotyledons of norflurazon-treated soybeans [ Glycine max (L.) Merr. cv. 'Hill']. Antiserum prepared to NR isolated from Chlorella strongly reacted against NR from norflurazon-treated cotyledons. This serum inhibited the NR activity in crude extracts of norflurazon-treated soybean cotyledons by 98% even at a 1:2000 dilution of crude serum. Pre-immune serum had no effect on the activity. These data indicate that there are similar antigenic determinants at the active site of both Chlorella and norflurazon-treated soybean NR. Whole cotyledons were homogenized in lithium dodecyl sulfate-containing buffer, electrophoretically separated and blotted to nitrocellulose. When the blots were reacted with the anti-NR serum only a single protein (M_r= 98 kdalton) was visualized. Immunofluorescence studies on fixed tissue sections revealed intense fluorescence in the cytoplasm. Weaker reactions were associated with organelles tentatively identified as plastids. Pre-immune serum controls were completely unstained using immunocytochemical procedures.     

Ataxin1L Is a Regulator of HSC Function Highlighting the Utility of Cross-Tissue Comparisons for Gene Discovery

Hematopoietic stem cells (HSCs) are rare quiescent cells that continuously replenish the cellular components of the peripheral blood. Observing that the ataxia-associated gene Ataxin-1-like (Atxn1L) was highly expressed in HSCs, we examined its role in HSC function through in vitro and in vivo assays. Mice lacking Atxn1L had greater numbers of HSCs that regenerated the blood more quickly than their wild-type counterparts. Molecular analyses indicated Atxn1L null HSCs had gene expression changes that regulate a program consistent with their higher level of proliferation, suggesting that Atxn1L is a novel regulator of HSC quiescence. To determine if additional brain-associated genes were candidates for hematologic regulation, we examined genes encoding proteins from autism- and ataxia-associated protein–protein interaction networks for their representation in hematopoietic cell populations. The interactomes were found to be highly enriched for proteins encoded by genes specifically expressed in HSCs relative to their differentiated progeny. Our data suggest a heretofore unappreciated similarity between regulatory modules in the brain and HSCs, offering a new strategy for novel gene discovery in both systems.     

Matrix Metalloproteinase 9 Exerts Antiviral Activity against Respiratory Syncytial Virus

Increased lung levels of matrix metalloproteinase 9 (MMP9) are frequently observed during respiratory syncytial virus (RSV) infection and elevated MMP9 concentrations are associated with severe disease. However little is known of the functional role of MMP9 during lung infection with RSV. To determine whether MMP9 exerted direct antiviral potential, active MMP9 was incubated with RSV, which showed that MMP9 directly prevented RSV infectivity to airway epithelial cells. Using knockout mice the effect of the loss of Mmp9 expression was examined during RSV infection to demonstrate MMP9’s role in viral clearance and disease progression. Seven days following RSV infection, Mmp9 ^-/- mice displayed substantial weight loss, increased RSV-induced airway hyperresponsiveness (AHR) and reduced clearance of RSV from the lungs compared to wild type mice. Although total bronchoalveolar lavage fluid (BALF) cell counts were similar in both groups, neutrophil recruitment to the lungs during RSV infection was significantly reduced in Mmp9 ^-/- mice. Reduced neutrophil recruitment coincided with diminished RANTES, IL-1β, SCF, G-CSF expression and p38 phosphorylation. Induction of p38 signaling was required for RANTES and G-CSF expression during RSV infection in airway epithelial cells. Therefore, MMP9 in RSV lung infection significantly enhances neutrophil recruitment, cytokine production and viral clearance while reducing AHR.     

A neurological integrator for the oculomotor control system

This paper describes a mathematical model of a neurological integrator that has been developed to provide the very long leakage time constant required of the intgrator in the oculomotor system. The Gaussian distribution of cell thresholds and the eye-position- related discharge of the individual cells of the integrator model, and the highly specialized short-duration, high-frequency burst required of the input, have been modeled after the single-cell behavior actually observed in the oculomotor control areas of the brain stem of an alert primate.     

Early and late replicative chromosomal banding patterns of Gallus domesticus.

Early and late replicating chromosomal banding patterns of Gallus domesticus were investigated by cell synchronization and incorporation of 5'-bromodeoxyuridine during early and late DNA synthesis. The early replicating chromosomal banding patterns observed, as revealed by either acridine orange or Hoechst 33258/propidium iodide staining, were similar to the structural G-banding patterns obtained by trypsin digestion and Giemsa staining. Late replicating chromosomal banding showed extensive reverse band complementarity to the G-banding pattern. Cell synchronization increased the number of prometaphase and metaphase plates available for analysis. G-banding obtained by Hoechst 33258/propidium iodide staining was investigated due to the fact that it is compatible with chromosomal in situ hybridization procedures that use nonisotopically-labeled DNA probes. Standard replicative G-banded and R-banded idiograms, as obtained after cell synchronization, are proposed.     

Comprehensive profiling of accessible surface glycans of mammalian sperm using a lectin microarray

It is well known that cell surface glycans or glycocalyx play important roles in sperm motility, maturation and fertilization. A comprehensive profile of the sperm surface glycans will greatly facilitate both basic research (sperm glycobiology) and clinical studies, such as diagnostics of infertility. As a group of natural glycan binders, lectin is an ideal tool for cell surface glycan profiling. However, because of the lack of effective technology, only a few lectins have been tested for lectin-sperm binding profiles. To address this challenge, we have developed a procedure for high-throughput probing of mammalian sperm with 91 lectins on lectin microarrays. Normal sperm from human, boar, bull, goat and rabbit were collected and analyzed on the lectin microarrays. Positive bindings of a set of ~50 lectins were observed for all the sperm of 5 species, which indicated a wide range of glycans are on the surface of mammalian sperm. Species specific lectin bindings were also observed. Clustering analysis revealed that the distances of the five species according to the lectin binding profiles are consistent with that of the genome sequence based phylogenetic tree except for rabbit. The procedure that we established in this study could be generally applicable for sperm from other species or defect sperm from the same species. We believe the lectin binding profiles of the mammalian sperm that we established in this study are valuable for both basic research and clinical studies.     

Ultraviolet photoelectron studies of 5-halouracils

Ultravoilet photoelectron spectroscopy has been employed to exmamin the valence electronic structure of 5-fluorouracil, 5-chlorouracil, 5-bromouracil, and 5-iodouracil. Photoelectron bands associted with the three highest π orbitals and the two oxygen atom lone-pair orbitals were assigned by a comparison to similar bands observed in the photoelectron spectrum of uraciul. Bands arising from the halogen atom lone-pair orbitals were assigned by comparing the present results with photoelectron spectra measured for halobenzenes, and by considering the linear dependence of halogen atom lone-pair ionization potentials upon halogen atom electronegativities. The present spectroscopic results have been compared with results from studies of association constants of 5-halouracil–adenine complexes. This examination in dicates that the complex association constants incresase as the ionization potentials of the highest occupied π orbital and the halogen atom lone-pair orbitals of th halouracils decrease.     

Regulation of Rhodopsin-eGFP Distribution in Transgenic Xenopus Rod Outer Segments by Light

The rod outer segment (OS), comprised of tightly stacked disk membranes packed with rhodopsin, is in a dynamic equilibrium governed by a diurnal rhythm with newly synthesized membrane inserted at the OS base balancing membrane loss from the distal tip via disk shedding. Using transgenic Xenopus and live cell confocal imaging, we found OS axial variation of fluorescence intensity in cells expressing a fluorescently tagged rhodopsin transgene. There was a light synchronized fluctuation in intensity, with higher intensity in disks formed at night and lower intensity for those formed during the day. This fluctuation was absent in constant light or dark conditions. There was also a slow modulation of the overall expression level that was not synchronized with the lighting cycle or between cells in the same retina. The axial variations of other membrane-associated fluorescent proteins, eGFP-containing two geranylgeranyl acceptor sites and eGFP fused to the transmembrane domain of syntaxin, were greatly reduced or not detectable, respectively. In acutely light-adapted rods, an arrestin-eGFP fusion protein also exhibited axial variation. Both the light-sensitive Rho-eGFP and arrestin-eGFP banding were in phase with the previously characterized birefringence banding (Kaplan, Invest. Ophthalmol. Vis. Sci. 21, 395–402 1981). In contrast, endogenous rhodopsin did not exhibit such axial variation. Thus, there is an axial inhomogeneity in membrane composition or structure, detectable by the rhodopsin transgene density distribution and regulated by the light cycle, implying a light-regulated step for disk assembly in the OS. The impact of these results on the use of chimeric proteins with rhodopsin fused to fluorescent proteins at the carboxyl terminus is discussed.