Two combinatorial patterns of telomere histone marks in plants with canonical and non‐canonical telomere repeats

Telomeres, nucleoprotein structures at the ends of linear eukaryotic chromosomes, are crucial for the maintenance of genome integrity. In most plants, telomeres consist of conserved tandem repeat units comprising the TTTAGGG motif. Recently, non‐canonical telomeres were described in several plants and plant taxons, including the carnivorous plant Genlisea hispidula (TTCAGG/TTTCAGG), the genus Cestrum (Solanaceae; TTTTTTAGGG), and plants from the Asparagales order with either a vertebrate‐type telomere repeat TTAGGG or Allium genus‐specific CTCGGTTATGGG repeat. We analyzed epigenetic modifications of telomeric histones in plants with canonical and non‐canonical telomeres, and further in telomeric chromatin captured from leaves of Nicotiana benthamiana transiently transformed by telomere CRISPR‐dCas9‐eGFP, and of Arabidopsis thaliana stably transformed with TALE_telo C‐3×GFP. Two combinatorial patterns of telomeric histone modifications were identified: (i) an Arabidopsis‐like pattern (A. thaliana, G. hispidula, Genlisea nigrocaulis, Allium cepa, Narcissus pseudonarcissus, Petunia hybrida, Solanum tuberosum, Solanum lycopersicum) with telomeric histones decorated predominantly by H3K9me2; (ii) a tobacco‐like pattern (Nicotiana tabacum, N. benthamiana, C. elegans) with a strong H3K27me3 signal. Our data suggest that epigenetic modifications of plant telomere‐associated histones are related neither to the sequence of the telomere motif nor to the lengths of the telomeres. Nor the phylogenetic position of the species plays the role; representatives of the Solanaceae family are included in both groups. As both patterns of histone marks are compatible with fully functional telomeres in respective plants, we conclude that the described specific differences in histone marks are not critical for telomere functions.     

Inverse identification of local stiffness across ascending thoracic aortic aneurysms

Biomechanics and Modeling in Mechanobiology - Aortic dissection is the most common catastrophe of the thoracic aorta, with a very high rate of mortality. Type A dissection is often associated with...     

Morphological characteristics and performance variables of women soccer players

The purpose of this study was to describe certain morphological characteristics of women soccer players and to examine aspects of training and performance. Twenty-two anthropometric sites were used in measurements of somatotype and body composition; flexibility, agility, anaerobic power, leg muscle power, and dynamic pulmonary functions were used as performance variables. Measurements were made on 17 professional athletes and 17 age-matched sedentary women who acted as controls. The women soccer players showed less fat content and less lean body mass than did the sedentary women. The mean somatotype for the soccer players was 3.07-3.55-2.43 and for the nonathletes was 3.57-3.35-2.90. Anaerobic power, leg muscle power, and agility in the athletes were higher than in the nonathletes, whereas no differences were found in flexibility and pulmonary functions (p > 0.05). The women soccer players showed more significantly mesomorphic, less endomorphic, least ectomorphic components and higher performance level than did the sedentary women.     

Comparison of three rat models of cerebral vasospasm

A substantial number of rat models have been used to research subarachnoid hemorrhage-induced cerebral vasospasm; however, controversy exists regarding which method of selection is appropriate for this species. This study was designed to provide extensive information about the three most popular subarachnoid hemorrhage rat models: the endovascular puncture model, the single-hemorrhage model, and the double-hemorrhage model. In this study, the basilar artery and posterior communicating artery were chosen for histopathological examination and morphometric analysis. Both the endovascular puncture model and single-hemorrhage model developed significant degrees of vasospasm, which were less severe when compared with the double-hemorrhage model. The endovascular puncture model and double-hemorrhage model both developed more vasospasms in the posterior communicating artery than in the basilar artery. The endovascular puncture model has a markedly high mortality rate and high variability in bleeding volume. Overall, the present study showed that the double-hemorrhage model in rats is a more suitable tool with which to investigate mechanism and therapeutic approaches because it accurately correlates with the time courses for vasospasm in humans.     

From Sensory Signals to Modality-Independent Conceptual Representations: A Probabilistic Language of Thought Approach

People learn modality-independent, conceptual representations from modality-specific sensory signals. Here, we hypothesize that any system that accomplishes this feat will include three components: a representational language for characterizing modality-independent representations, a set of sensory-specific forward models for mapping from modality-independent representations to sensory signals, and an inference algorithm for inverting forward models—that is, an algorithm for using sensory signals to infer modality-independent representations. To evaluate this hypothesis, we instantiate it in the form of a computational model that learns object shape representations from visual and/or haptic signals. The model uses a probabilistic grammar to characterize modality-independent representations of object shape, uses a computer graphics toolkit and a human hand simulator to map from object representations to visual and haptic features, respectively, and uses a Bayesian inference algorithm to infer modality-independent object representations from visual and/or haptic signals. Simulation results show that the model infers identical object representations when an object is viewed, grasped, or both. That is, the model’s percepts are modality invariant. We also report the results of an experiment in which different subjects rated the similarity of pairs of objects in different sensory conditions, and show that the model provides a very accurate account of subjects’ ratings. Conceptually, this research significantly contributes to our understanding of modality invariance, an important type of perceptual constancy, by demonstrating how modality-independent representations can be acquired and used. Methodologically, it provides an important contribution to cognitive modeling, particularly an emerging probabilistic language-of-thought approach, by showing how symbolic and statistical approaches can be combined in order to understand aspects of human perception.     

Cellulolytic, fermentative, and methanogenic guilds in benthic periphyton mats from the Florida Everglades

Phosphorus enrichment caused by runoff from agricultural areas has resulted in ecosystem-level changes in the northern Florida Everglades, including a loss of periphyton mats from nutrient-impacted areas. The potential for methanogenesis resulting from the anaerobic decomposition of cellulose and fermentation products, and the microorganisms responsible for these processes, were studied in mats from a region not impacted by nutrient enrichment. Methane was produced from periphyton incubated with cellulose, propionate, butyrate, and formate, with an accumulation of fatty acids in incubations. The accumulation of fatty acids may have been caused by the inhibition of syntrophic oxidation, a potentially significant route for methane production in soils. Sequence analysis of 16S rRNA genes characteristic of Clostridium, the primary genus responsible for anaerobic decomposition and fermentation in soils of the area, indicated that Clostridium Cluster I assemblages present in the mat differed from those in the soils of the area. Significantly, sequences characteristic of the Clostridium group that dominates the soils of the area, group XIV, were not detected in the mat. These results indicate that benthic periphyton is probably a significant source of methane in the Everglades, and the responsible microorganisms differ significantly from those in the soils of the area.