CENP-C unwraps the human CENP-A nucleosome through the H2A C-terminal tail

Centromeres are defined epigenetically by nucleosomes containing the histone H3 variant CENP-A, upon which the constitutive centromere-associated network of proteins (CCAN) is built. CENP-C is considered to be a central organizer of the CCAN. We provide new molecular insights into the structure of human CENP-A nucleosomes, in isolation and in complex with the CENP-C central region (CENP-C-CR), the main CENP-A binding module of human CENP-C. We establish that the short alpha N helix of CENP-A promotes DNA flexibility at the nucleosome ends, independently of the sequence it wraps. Furthermore, we show that, in vitro, two regions of human CENP-C (CENP-C-CR and CENP-C-motif) both bind exclusively to the CENP-A nucleosome. We find CENP-C-CR to bind with high affinity due to an extended hydrophobic area made up of CENP-A(V)(532) and CENP-A(V)(533). Importantly, we identify two key conformational changes within the CENP-A nucleosome upon CENP-C binding. First, the loose DNA wrapping of CENP-A nucleosomes is further exacerbated, through destabilization of the H2A C-terminal tail. Second, CENP-C-CR rigidifies the N-terminal tail of H4 in the conformation favoring H4(K20) monomethylation, essential for a functional centromere

Probing the gateway to superheavy nuclei in cranked relativistic Hartree-Bogoliubov theory

The cranked relativistic Hartree+Bogoliubov theory has been applied for a systematic study of the nuclei around 254No, the heaviest nuclei for which detailed spectroscopic data are available. The deformation, rotational response, pairing correlations, quasi-particle and other properties of these nuclei have been studied with different relativistic mean field (RMF) parametrizations. For the first time, the quasi-particle spectra of odd deformed nuclei have been calculated in a fully self-consistent way within the framework of the RMF theory. The energies of the spherical subshells, from which active deformed states of these nuclei emerge, are described with an accuracy better than 0.5 MeV for most of the subshells with the NL1 and NL3 parametrizations. However, for a few subshells the discrepancy reach 0.7-1.0 MeV. The implications of these results for the study of superheavy nuclei are discussed.Comment: 7 pages, 3 figures, Proceedings of the Conference on Frontiers of Nuclear Structure, Berkeley, California, July 29th - August 2nd, 2002, UC Berkeley, Clark Kerr Campus, in pres

valuation of rapeseed genotypes for yield and oil quality under rainfed conditions of district Mansehra

Five rapeseed genotypes were evaluated for agronomic parameters, yield, oil quantity and quality. Significant differences were observed for all the parameters except oil and protein percentage. The genotype Siren outperformed the rest of genotypes in yield potential (1104 kg/ha), followed by MRS-1 (866.67 kg/ha). For yield contributing characters like length of inflorescence and pods per plant, genotype Siren again showed good results that are, 51.3 cm and 136.5 pods/plant, respectively. The genotype Siren also showed low glucosinolate (44.82 ìmol/g), erucic acid (23.67 ìmol/g) and higher amounts of oleic acid (59.01%). Due to its high yield and oil quality, the genotype Siren is recommended for general cultivation in the area and further use in breeding programmes for Brassica napus

Insecticide Resistance and Effect of Piperonyl Butoxide as a Synergist in Three Strains of Aedes Aegypti (Linn.) (Diptera: Culicidae) Against Insecticides Permethrin, Cypermethrin, and D-allethrin

Tiga strain nyamuk Aedes aegypti yang dipelihara di laboratorium dan dikoleksi dari lapangan diuji menggunakan tiga jenis insektisida dari golongan piretroid (permetrin, cypermetrin, dan d-alletrin) dengan metode bottle bioassay untuk mengetahui tingkatan dan mekanisme dari resistensi yang terjadi terhadap insektisida piretroid. Hasil penelitian menunjukkan bahwa ketiga strain yang diuji kemungkinan telah resisten terhadap ketiga insektisida tersebut, termasuk strain-strain yang telah dipelihara selama beberapa generasi di laboratorium, yang diindikasikan dengan nilai LT90 yang tinggi. Hasil ini mengindikasikan bahwa terdapat aktivitas MFO (Mixed-Function Oxidase) pada ketiga strain yang diuji, di mana mekanisme tersebut mungkin berperan dalam menimbulkan resistensi pada ketiga strain, meskipun diduga terdapat mekanisme lain yang juga ikut terlibat

Some changes in the physical qualities of muscle lipid of the freshwater murrel, Ophicephalus striatus (bloch.) during storage

The present communication reports the changes in the specific gravity, coefficient of viscosity, fluidity and surface tension of the muscle lipid of O. striatus, a common freshwater murrel, when stored at room temp (32 ± 2°C) The specific gravity of muscle lipid was found to rise from 0.894 to 0.912 during the first 25 days of storage but registered the highest (0.925) when stored for 50 days. Surface tension seemed to rise with the duration of storage. This was, presumably, due to an increase in the forces with which the molecules in the surface of the lipid tended to compress the molecules below to the smallest possible volume. During the period of storage marked changes seemed to occur in the direction of an increase in the value of the coefficient of viscosity and a reciprocal decline in the fluidity. Evidently, the observed increase in the viscosity seemed to be the result of increased internal friction between different molecular layers of the lipid, whereas a decline in the fluidity was perhaps the consequence of its inverse correlation with the coefficient of viscosity

Dynamic organization schemes for cooperative proxy caching

In a generic cooperative caching architecture, web proxies form a mesh network. When a proxy cannot satisfy a request, it forwards the request to the other nodes of the mesh. Since a local cache cannot fulfill the majority of the arriving requests (typical values of the local hit ratio are about 30-50%), the volume of queries diverted to neighboring nodes can substantially grow and may consume considerable amount of system resources. A proxy does not need to cooperate with every node of the mesh due to the following reasons: (i) the traffic characteristics may be highly diverse; (ii) the contents of some nodes may extensively overlap; (iii) the inter-node distance might be too large. Furthermore, organizing N proxies in a mesh topology introduces scalability problems, since the number of queries is of the order of N/sup 2/. Therefore, restricting the number of neighbors for each proxy to k < N - 1 will likely lead to a balanced trade-off between query overhead and hit ratio, provided cooperation is done among useful neighbors. For a number of reasons the selection of useful neighbors is not efficient. An obvious reason is that web access patterns change dynamically. Furthermore, availability of proxies is not always globally known. This paper proposes a set of algorithms that enable proxies to independently explore the network and choose the k most beneficial (according to local criteria) neighbors in a dynamic fashion. The simulation experiments illustrate that the proposed dynamic neighbor reconfiguration schemes significantly reduce the overhead incurred by the mesh topology while yielding higher hit ratios compared to the static approach.published_or_final_versio

Associations between adult attachment and vision-related quality of life in visually impaired individuals

PURPOSE An attachment theory framework approach may allow insight into how social and psychosocial factors interact to impact vision-related quality of life (QoL). In this pilot study, we investigated potential associations between adult attachment style and visual function QoL of visually impaired individuals. METHODS We recruited 38 visually impaired individuals (15 females, 23 males; 51.8 ± 16.0 years). Visual function measures included distance and near visual acuity (VA) and contrast sensitivity. All participants completed: the 25-item National Eye Institute Visual Functioning Questionnaire-25 (NEI-VFQ 25) and the Experiences in Close Relationships–Relationships Structures questionnaire. RESULTS Presenting conditions included inherited retinal dystrophy (n = 10), nystagmus (n = 9), glaucoma (n = 7) and other eye conditions (n = 12). There was a statistically significant negative correlation between the NEI-VFQ-25 composite score (45.5 ± 14.7) and attachment-related anxiety (r = −0.352, p = 0.033). The latter correlation still held when controlling for participants’ level of vision (r = −0.352, p = 0.035). Despite the range of conditions and wide age range, these were not significantly correlated with any variable of interest in the current study. CONCLUSION Attachment-related anxiety ought to be taken into account when managing a visually impaired individual. Attachment-based approaches could be used to improve access to support services for visually impaired individuals, as well as self-management of their condition