Identification of Sperm Chromatin Proteins as Candidate Markers of Stallion Fertility

During spermatogenesis, histones are largely replaced by transition proteins and protamines in normal stallions. Incomplete nucleoprotein exchange results in the abnormal retention of histones and transition proteins, which is an indicator of poor sperm quality. Equine nucleoprotein exchange has not previously been investigated in detail, so that equine sperm chromatin quality problems, which are often responsible for poor breeding performance of stallions, are not well understood. In order to characterize chromatin remodeling events in stallion spermatogenesis and to identify proteins indicative of sperm chromatin defects, such as excessive amounts of histones, we identified antibodies that recognize equine testis-specific proteins of interest. Immunoblotting of testis and sperm protein lysates and immunofluorescence staining of histological tissue sections were used to identify candidate marker proteins of incomplete sperm chromatin maturation. Results of the study, which represents the first comprehensive characterization of the nucleoprotein exchange during spermatogenesis in the stallion, challenge the paradigm that the main function of histone H4 lysine (hyper-) acetylation (concomitant H4K5 and H4K8 acetylation) is to facilitate nucleosome ejection during spermatid nuclear elongation to allow for transition protein and protamine insertion into the chromatin. That paradigm was based on observations in mice and rats where H4 acetylation in several lysine residues occurs just prior to or during nuclear elongation. In contrast, the equine data presented here show strong acetylation of H4 in K5, K8 and K12 positions immediately after meiosis in round spermatids, independent of nuclear transition protein 1 deposition. Furthermore, results of H4K16 acetylation analyses underline the importance of this mark, which is likely mediated by DNA damage signaling pathways, emphasizing the importance of DNA repair processes for the exchange of nucleoprotein exchange in spermiogenesis and therefore, in extension, for male fertility. In addition, a revised description of the equine spermatogenic cycle is proposed here that is better aligned with human, mouse and rat spermatogenesis. Finally, the testis-specific histone variant TH2B was identified as a potential quantitative marker of equine sperm quality

The oceanography of the New York Bight

The New York Bight consists of the waters lying between Cape May, New Jersey, and Montauk Point, Long Island. A portion of the general southwesterly current known as the Coastal Drift lies in the seaward part of the Bight. Inshore from the Coastal Drift is an area of complex hydrography where the combined outflows of the Hudson River and other rivers enter the sea. In the region where the New Jersey and Long Island coastlines converge, an area 25 nautical miles on each side has been studied at all seasons of the year. This area extends from Sandy Hook southward to a point off Seaside Heights, eastward to 73°15' W longitude, north to the Long Island shore, and westward to Rockaway Inlet. The depth of water in the area averages about 90 feet, except in the innermost part of the Hudson Canyon which runs roughly northwest-southeast across most of the survey area. In the Canyon, depths in excess of 240. feet are found within the limits of the area studied. The hydrographic conditions in the area are in essence similar to those off the mouths of other large rivers. The combined flows of the Hudson and other rivers entering the surveyed area discharge enough fresh water annually to replace about one-half of the total volume of water under the 600 square miles of sea surface extensively surveyed. The salinity within the area is nearly as high as that of adjacent coastal water, however, and the actual quantity of river water within the area at any time rarely exceeds one percent of the total volume of water. Quantitative evaluation of these factors has led to the conclusion that there is an active circulation within the area which rapidly disperses the introduced river effluent. Many surveys of coastal and estuarine waters have been made. Outstanding among these are the survey of the River Tees, (1931, 1935), of the Tamar Estuary, (Hartley and Spooner, 1938; Milne, 1938), and of Alberni Inlet, (Tully, 1949). The general principles of estuarine circulations may be summarized as follows: In order to remove the added river water there must be a non-tidal drift of mixed water in a net seaward direction. When river flow remains constant, a steady state distribution of fresh and salt water throughout the estuary is attained, and at such times the net transport of river water seaward through any complete cross section of the estuary exactly equals the contribution of fresh water from the river during the same interval of time. As the mixture containing the river water moves seaward it gets progressively more saline, as additional sea water is entrained. In order to provide this sea water there must be a counter drift having a net flow in a landward direction. Superimposed on these necessary parts of the circulation are tidal and wind currents. The velocities of the tidal currents are commonly much greater than the velocity of the non-tidal drift, making the latter difficult to measure directly. It can be inferred, however, from the distribution of river water, as derived from the salinity distribution. Using the river water in this way we have evaluated the exchanges of the waters within the New York Bight. Tully (1949) has analyzed the circulation in Alberni Inlet by similar methods. Tidal current measurements made by the Coast and Geodetic Survey at various locations in the northwestern corner of the surveyed area are summarized by Marmer (1935). At Scotland Lightship, which is the location of the stations at the western end of Section A in Figure 1, the total excursion which results from the flood or ebb tidal currents is less than two miles. The currents at Ambrose Lightship, about five miles to the eastward, produce displacements only about half as great. The tidal displacements throughout the rest of the area are presumed to be less than these. The pattern of distribution of properties will be displaced, therefore, a distance less than ±1 mile at various stages of the tide. This distance is small in comparison to the size of the area surveyed, especially when considering the fact that distances between stations ranged from 5 to 8 miles. It was unnecessary, therefore, to attempt to take comparable stations at similar stages of the tide. Other considerations, beside its interesting hydrography, have contributed to the choice of this area for study. Because it is adjacent to centers of dense population and heavy industrial concentration, the New York Bight serves the conflicting purposes of waste disposal and recreation. Sewer effluents and industrial wastes enter the area by way of the rivers. Sewage sludges are barged out and dumped within the region studied. During the period covered by our surveys, The National Lead Company commenced operations to barge and discharge at sea the waste from its titanium plant at Sayreville, New Jersey. Since iron was a major constituent of this waste, analyses for iron in the water were made at each station, and the results have been valuable in checking the rate of the circulation which was computed from the distribution of river effluent. The New York Bight is also used extensively for recreational purposes. Because the area is readily and cheaply accessible by public transportation it must serve the recreational demands of a large part of the population of metropolitan New York. Sport fishing, bathing and boating are the principal recreational activities. Small but valuable commercial fisheries for shellfish and fin-fish also exist. The purpose of this study was to investigate the hydrographic processes in the New York Bight since they have an important bearing on the general problems of coastal oceanography and a knowledge of them should lead to a more successful evaluation and utilization of the area for the diverse purposes it must serve

Heritable Sperm Chromatin Epigenetics: A Break to Remember

Sperm chromatin not only has a unique structure to condense and protect the paternal DNA in transit, but also provides epigenetic information that supports embryonic development. Most of the unique sperm nuclear architecture is formed during the sweeping postmeiotic chromatin remodeling events in spermiogenesis, where the majority of nucleosomes are removed and replaced by protamines. The remaining histones and other chromatin proteins are located in structurally and transcriptionally relevant positions in the genome and carry diverse post-translational modifications relevant to the control of embryonic gene expression. How such postmeiotic chromatin-based programming of sperm epigenetic information proceeds, and how susceptible the process is to modulation by exogenous factors are key questions for understanding the inheritance of acquired epigenetic marks through the male germ line. We propose that transient DNA strand breaks mediated by topoisomerase II beta and the subsequent activation of DNA damage response pathways result in defined post-translational modifications of histones in spermiogenesis. These pathways, likely along with others, may contribute to chromatin remodeling in elongating spermatids, influence chromatin-based intergenerational inheritance of epigenetic information, and may be defective in pathologies of abnormal male gametogenesis and infertility

Social Competence Treatment after Traumatic Brain Injury: A Multicenter, Randomized, Controlled Trial of Interactive Group Treatment versus Non-Interactive Treatment

Objective To evaluate the effectiveness of a replicable group treatment program for improving social competence after traumatic brain injury (TBI). Design Multicenter randomized controlled trial comparing two methods of conducting a social competency skills program, an interactive group format versus a classroom lecture. Setting Community and Veteran rehabilitation centers. Participants 179 civilian, military, and veteran adults with TBI and social competence difficulties, at least 6 months post-injury. Experimental Intervention Thirteen weekly group interactive sessions (1.5 hours) with structured and facilitated group interactions to improve social competence. Alternative (Control) Intervention Thirteen traditional classroom sessions using the same curriculum with brief supplemental individual sessions but without structured group interaction. Primary Outcome Measure Profile of Pragmatic Impairment in Communication (PPIC), an objective behavioral rating of social communication impairments following TBI. Secondary Outcomes LaTrobe Communication Questionnaire (LCQ), Goal Attainment Scale (GAS), Satisfaction with Life Scale (SWLS), Post-Traumatic Stress Disorder Checklist – (PCL-C), Brief Symptom Inventory 18 (BSI-18), Scale of Perceived Social Self Efficacy (PSSE). Results Social competence goals (GAS) were achieved and maintained for most participants regardless of treatment method. Significant improvements in the primary outcome (PPIC) and two of the secondary outcomes (LCQ and BSI) were seen immediately post-treatment and at 3 months post-treatment in the AT arm only, however these improvements were not significantly different between the GIST and AT arms. Similar trends were observed for PSSE and PCL-C. Conclusions Social competence skills improved for persons with TBI in both treatment conditions. The group interactive format was not found to be a superior method of treatment delivery in this study

Comparative genomics and understanding of microbial biology.

The sequences of close to 30 microbial genomes have been completed during the past 5 years, and the sequences of more than 100 genomes should be completed in the next 2 to 4 years. Soon, completed microbial genome sequences will represent a collection of >200,000 predicted coding sequences. While analysis of a single genome provides tremendous biological insights on any given organism, comparative analysis of multiple genomes provides substantially more information on the physiology and evolution of microbial species and expands our ability to better assign putative function to predicted coding sequences

Orbital Instabilities in a Triaxial Cusp Potential

This paper constructs an analytic form for a triaxial potential that describes the dynamics of a wide variety of astrophysical systems, including the inner portions of dark matter halos, the central regions of galactic bulges, and young embedded star clusters. Specifically, this potential results from a density profile of the form $\rho (m) \propto m^{-1}$, where the radial coordinate is generalized to triaxial form so that $m^2 = x^2/a^2 + y^2/b^2 + z^2/c^2$. Using the resulting analytic form of the potential, and the corresponding force laws, we construct orbit solutions and show that a robust orbit instability exists in these systems. For orbits initially confined to any of the three principal planes, the motion in the perpendicular direction can be unstable. We discuss the range of parameter space for which these orbits are unstable, find the growth rates and saturation levels of the instability, and develop a set of analytic model equations that elucidate the essential physics of the instability mechanism. This orbit instability has a large number of astrophysical implications and applications, including understanding the formation of dark matter halos, the structure of galactic bulges, the survival of tidal streams, and the early evolution of embedded star clusters.Comment: 50 pages, accepted for publication in Ap

Effects of Turbulence, Eccentricity Damping, and Migration Rate on the Capture of Planets into Mean Motion Resonance

Pairs of migrating extrasolar planets often lock into mean motion resonance as they drift inward. This paper studies the convergent migration of giant planets (driven by a circumstellar disk) and determines the probability that they are captured into mean motion resonance. The probability that such planets enter resonance depends on the type of resonance, the migration rate, the eccentricity damping rate, and the amplitude of the turbulent fluctuations. This problem is studied both through direct integrations of the full 3-body problem, and via semi-analytic model equations. In general, the probability of resonance decreases with increasing migration rate, and with increasing levels of turbulence, but increases with eccentricity damping. Previous work has shown that the distributions of orbital elements (eccentricity and semimajor axis) for observed extrasolar planets can be reproduced by migration models with multiple planets. However, these results depend on resonance locking, and this study shows that entry into -- and maintenance of -- mean motion resonance depends sensitively on migration rate, eccentricity damping, and turbulence.Comment: 43 pages including 14 figures; accepted for publication in The Astrophysical Journa

Dynamic Soil-Foundation-Structure Interaction Analyses of Large Caissons

Large cellular reinforced concrete caissons exist as foundations of major long-span bridges across waterways in many parts of the country. This study was conducted to evaluate the important factors affecting the seismic response of large caissons. The paper presents the results of equivalent linear and non-linear analyses performed for a typical caisson idealized based on the cellular caisson at Pier W3 of the West San Francisco Bay Bridge subject to ground motion with a peak rock acceleration of 0.6 g. This caisson is 38.7 m (127 fi) long by 22.9 m (75 ft) wide submerged in about 32.6 m (107 ft) of water. It is embedded in 33.5 m (110 fi) of soil deposits and is founded on rock. Equivalent linear 3-D and 2-D analyses conducted in the direction of the short axis (longitudinal) were performed using a modified version of computer program SASSI. The results of these 3-D and 2-D analyses are similar. Non-linear analyses were performed for 2-D models using computer program FLAC. The results indicate that side gapping, base lifting, interface sliding, and soil yielding reduce the earth pressure, base bearing stress, caisson shear and bending moment, and caisson motions. However, the frequency characteristics of the responses appear to be relatively unaffected