946 research outputs found

    Processes that Regulate the Ubiquitination of Chromatin and Chromatin-Associated Proteins

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    Ubiquitin is a post-translational modification important for many different processes in the cell, including antigen presentation and proteosomal degradation of proteins. It is heavily involved in the regulation of chromatin and the proteins that control chromatin-related processes. In this review, we will focus on ubiquitin-based chromatin regulation involved in four different processes. The first is DNA double strand break (DSB) repair and the role that ubiquitin plays in not just recruiting and stimulating DSB repair, but also the choice of pathway. The second is the PAF1 complex, which is involved in transcriptional elongation and interacts with RNAPII. The third is polycomb repressive complexes, specifically polycomb repressive complex 1, which utilizes ubiquitin to repress constitutively inactive genes. The last role of ubiquitin discussed is ubiquitin as a mitotic bookmark, which serves to provide a record of -active genes as cells transit mitosis. Each of these processes has independent pathways, but each is necessary for proper cellular function and organismal health

    The early life history of swordfish (Xiphias gladius) in the western North Atlantic

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    Lengths and ages of sword-fish (Xiphias gladius) estimated from increments on otoliths of larvae collected in the Caribbean Sea, Florida Straits, and off the southeastern United States, indicated two growth phases. Larvae complete yolk and oil globule absorption 5 to 6 days after hatching (DAH). Larvae 11 mm eat exclusively neustonic fish larvae. This diet indicates that young larvae <11 mm occupy the near-surface pelagia, whereas, older and longer larvae are neustonic. Spawning dates for larvae collected in various regions of the western North Atlantic, along with the abundance and spatial distribution of the youngest larvae, indicate that spawning peaks in three seasons and in five regions. Swordfish spawn in the Caribbean Sea, or possibly to the east, in winter, and in the western Gulf of Mexico in spring. Elsewhere swordfish spawn year-round, but spawning peaks in the spring in the north-central Gulf of Mexico, in the summer off southern Florida, and in the spring and early summer off the southeastern United States. The western Gulf Stream frontal zone is the focus of spawning off the southeastern coast of the United States, whereas spawning in the Gulf of Mexico seems to be focused in the vicinity of the Gulf Loop Current. Larvae may use the Gulf of Mexico and the outer continental shelf off the east coast of the United States as nursery areas. Some larvae may be transported northward, but trans-Atlantic transport of larvae is unlikely

    The Wind Chilled the Spectators, but the Wine Just Chilled: Sense, Structure, and Sentence Comprehension

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    Anticipation plays a role in language comprehension. In this article, we explore the extent to which verb sense influences expectations about upcoming structure. We focus on change of state verbs like shatter, which have different senses that are expressed in either transitive or intransitive structures, depending on the sense that is used. In two experiments we influence the interpretation of verb sense by manipulating the thematic fit of the grammatical subject as cause or affected entity for the verb, and test whether readers’ expectations for a transitive or intransitive structure change as a result. This sense-biasing context influenced reading times in the postverbal regions. Reading times for transitive sentences were faster following good-cause than good-theme subjects, but the opposite pattern was found for intransitive sentences. We conclude that readers use sense-contingent subcategorization preferences during on-line comprehension

    Atmospheric CO2 effect on stable carbon isotope composition of terrestrial fossil archives.

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    The 13C/12C ratio of C3 plant matter is thought to be controlled by the isotopic composition of atmospheric CO2 and stomatal response to environmental conditions, particularly mean annual precipitation (MAP). The effect of CO2 concentration on 13C/12C ratios is currently debated, yet crucial to reconstructing ancient environments and quantifying the carbon cycle. Here we compare high-resolution ice core measurements of atmospheric CO2 with fossil plant and faunal isotope records. We show the effect of pCO2 during the last deglaciation is stronger for gymnosperms (-1.4 ± 1.2‰) than angiosperms/fauna (-0.5 ± 1.5‰), while the contributions from changing MAP are -0.3 ± 0.6‰ and -0.4 ± 0.4‰, respectively. Previous studies have assumed that plant 13C/12C ratios are mostly determined by MAP, an assumption which is sometimes incorrect in geological time. Atmospheric effects must be taken into account when interpreting terrestrial stable carbon isotopes, with important implications for past environments and climates, and understanding plant responses to climate change

    Relationships between Larval and Juvenile Abundance of Winter-Spawned Fishes in North Carolina, USA

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    We analyzed the relationships between the larval and juvenile abundances of selected estuarine-dependent fishes that spawn during the winter in continental shelf waters of the U.S. Atlantic coast. Six species were included in the analysis based on their ecological and economic importance and relative abundance in available surveys: spot Leiostomus xanthurus, pinfish Lagodon rhomboides, southern flounder Paralichthys lethostigma, summer flounder Paralichthys dentatus, Atlantic croaker Micropogonias undulatus, and Atlantic menhaden Brevoortia tyrannus. Cross-correlation analysis was used to examine the relationships between the larval and juvenile abundances within species. Tests of synchrony across species were used to find similarities in recruitment dynamics for species with similar winter shelf-spawning life-history strategies. Positive correlations were found between the larval and juvenile abundances for three of the six selected species (spot, pinfish, and southern flounder). These three species have similar geographic ranges that primarily lie south of Cape Hatteras. There were no significant correlations between the larval and juvenile abundances for the other three species (summer flounder, Atlantic croaker, and Atlantic menhaden); we suggest several factors that could account for the lack of a relationship. Synchrony was found among the three southern species within both the larval and juvenile abundance time series. These results provide support for using larval ingress measures as indices of abundance for these and other species with similar geographic ranges and winter shelf-spawning life-history strategies

    Leveraging a Rapid, Round-the-Clock HIV Testing System to Screen for Acute HIV Infection in a Large Urban Public Medical Center

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    Methods The hospital laboratory performed round-the-clock rapid HIV antibody testing on venipuncture specimens from patients undergoing HIV testing in hospital and community clinics, inpatient settings, and the emergency department. For patients with negative results, a public health laboratory conducted pooled HIV RNA testing for acute HIV infection. The laboratories communicated positive results from the hospital campus to a linkage team. Linkage was defined as one outpatient HIV-related visit. Results Among 7,927 patients, 8,550 rapid tests resulted in 137 cases of HIV infection (1.7%, 95% CI 1.5%–2.0%), of whom 46 were new HIV diagnoses (0.58%, 95% CI 0.43%–0.77%). Pooled HIV RNA testing of 6,704 specimens (78.4%) resulted in 3 cases of acute HIV infection (0.05%, 95% CI 0.01%–0.14) and increased HIV case detection by 3.5%. Half of new HIV diagnoses and 2/3 of acute infections were detected in the emergency department and urgent care clinic. Rapid test sensitivity was 98.9% (95% CI 93.8%– 99.8%); specificity was 99.9% (95% CI 99.7%–99.9%). Over 95% of newly diagnosed and out-of-care HIV-infected patients were linked to care. Conclusions Patients undergoing HIV testing in emergency departments and urgent care clinics may benefit from being simultaneously screened for acute HIV infection
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