Cytoarchitectonics of ileocecal lymph nodes in newborn and sexually mature simians (pavian hamadrils)]

Cell composition of various components (cortical plateau, folliculi and cords) of ileocecal lymph nodes was studied in newborn, 1.5 and 2.5 months of age (2 animals) and in mature (3 animals) monkeys, Papio hamadryas. In histological sections obtained at the level of hilus of the lymph node cellular elements were counted by means of morphometric grid of Glagolev modifoed by S. B. Stefanov. The data obtained were statistically treated. Newborn and mature monkeys have their peculiar cytological profile in every structural component of the lymph node. The lymph nodes in the newborns contain much more reticular cells and young cellular forms (blast forms and large lymphocytes) than mature animals. In the newborns, the number of mitotically deviding cells in the cortical plateau and in folliculi is 6 times and in myelin cords 10 times as great as in mature monkeys. A much greater per cent of plasmatic cells in mature animals suggests their greater immunological activity. Age differences in cell composition of lymph nodes in young and mature monkeys seem to be connected with accumulation of cellular mass and growth of the node in young animals, as well as with general rearrangement of the organism as a whole (in particular with changes in nutrition, intensity of movement, hormonal background).     

Chromosome 6p influences on different dyslexia-related cognitive processes: further confirmation

In this study, which is a continuation and an extension of an earlier study, we enrolled two new families (N=31) and recruited more individuals from the previously ascertained families (N=56). The eight multiplex families (N=171) presented in this study were ascertained from a sample of adult probands whose childhood reading history is well documented through archival information. Six phenotypes were constructed to span a range of dyslexia-related cognitive processes. These phenotypes were (1) phonemic awareness (of spoken words); (2) phonological decoding (of printed nonwords); (3) rapid automatized naming (of colored squares or object drawings); (4) single-word reading (orally, of printed real words); (5) vocabulary; and (6) spelling (of dictated words). In addition, the diagnosis of lifelong dyslexia was established by clinical means. Genotyping was done with nine highly polymorphic markers from the 6p22.3-6p21.3 region. The results of two- and multipoint identity-by-descent and identity-by-state analyses supported the importance of a putative locus in the D6S464-D6S273 region for a number of dyslexia-related cognitive deficits.     

Coupling between the BLUF and EAL domains in the blue light-regulated phosphodiesterase BlrP1

The first biochemical and structural characterization of the full-length active photoreceptor BlrP1 from Klebsiella pneumoniae was recently reported by Barends et al. [Nature 459:1015–1018, (2009)]. The light-regulated catalytic function of its C-terminal c-di-guanosine monophosphate phosphodiesterase, the EAL (Glu-Ala-Leu) domain, is activated by the N-terminal sensor of blue light using the flavin adenine dinucleotide (BLUF) domain. We performed molecular dynamics simulations on the dimeric BlrP1 protein in order to examine the coupling regions that are presumably involved in transmitting light-induced structural changes which occur in the BLUF domain to the EAL domain. According to the results of simulations and an analysis of the hydrogen bonding between the respective polypeptide chains, the region containing the site on the α3α4 loop of BLUF is responsible for communication between the photosensing and catalytic domains in the dimeric BlrP1 protein.     

A charge-deficient analogue of spermine with chelating properties

1,12-Diamino-3,6,9-triazadodecane, a new isosteric and charge-deficient analogue of spermine, is synthesized. Unlike spermine, the new analogue is an excellent chelator of Cu2+ ions. Possible applications of this compound for studying enzymes of polyamine metabolism and cellular functions of spermine are discussed. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2005, vol. 31, no. 3; see also http://www.maik.ru.     

Effect of the global topology of the interplanetary magnetic field on the properties of impulsive acceleration processes in distant regions of the Earth’s magnetospheric tail

The paper is devoted to a statistical study of high-speed ion beams (beamlets) observed by the Interball-1 and Interball-2 satellites in the boundary region of the plasma sheet of the geomagnetic tail and in the high-latitude auroral regions of the Earth’s magnetosphere. Beamlets result from nonlinear acceleration processes occurring in the current sheet in the distant regions of the geomagnetic tail. They propagate toward the Earth along the magnetic field lines and are detected in the boundary region of the plasma sheet and near the high-latitude boundary of the plasma sheet in the auroral region in the form of short (with a duration of 1–2 min) bursts of high-energy (with energies of about several tens of keV) ions. The sizes of the latitudinal zones where the beamlets are localized in the tail and in the auroral region are determined using the epoch superposition method. The relationship between the frequency of beamlet generation in the boundary region of the plasma sheet and the prehistory of the direction of the interplanetary magnetic field (the magnitude of a clock angle) is investigated. It was established that this direction exerts a global effect on the beamlet generation frequency; moreover, it was found that the beamlet generation frequency in the midnight local time sector of the tail and at the flanks depends differently on the direction of the interplanetary magnetic field. In the midnight sector, the beamlets are observed at almost all directions of the interplanetary field, whereas the frequency of their generation at the flanks is maximal only when the interplanetary magnetic field has a large y component.     

QM/MM modeling the Ras-GAP catalyzed hydrolysis of guanosine triphosphate

The mechanism of the hydrolysis reaction of guanosine triphosphate (GTP) by the protein complex Ras-GAP (p21(ras) - p120(GAP)) has been modeled by the quantum mechanical-molecular mechanical (QM/MM) and ab initio quantum calculations. Initial geometry configurations have been prompted by atomic coordinates of a structural analog (PDBID:1WQ1). It is shown that the minimum energy reaction path is consistent with an assumption of two-step chemical transformations. At the first stage, a unified motion of Arg789 of GAP, Gln61, Thr35 of Ras, and the lytic water molecule results in a substantial spatial separation of the gamma-phosphate group of GTP from the rest of the molecule (GDP). This phase of hydrolysis process proceeds through the low-barrier transition state TS1. At the second stage, Gln61 abstracts and releases protons within the subsystem including Gln61, the lytic water molecule and the gamma-phosphate group of GTP through the corresponding transition state TS2. Direct quantum calculations show that, in this particular environment, the reaction GTP + H(2)O --> GDP + H(2)PO(4) (-) can proceed with reasonable activation barriers of less than 15 kcal/mol at every stage. This conclusion leads to a better understanding of the anticatalytic effect of cancer-causing mutations of Ras, which has been debated in recent years.     

Antibody CDR H3 modeling rules: extension for the case of absence of Arg H94 and Asp H101

The third complementary determining region of the immunoglobulin heavy chain (CDR H3) is one of the more difficult structures to model due to genetic reasons. However, the conformation of proximal to beta-framework ("torso") part of the CDR H3 is very predictable. Current "CDR's canonical classes" theory is based on identifying the key positions, H94 and H101. We can determine the CDR H3 "torso" structure if arginine or lysine is present in the H94 position and/or aspartic acid in the H101 position. We target the case characterized by the absence of key residues in both the H94 and H101 positions. There has not been discussion on this case in the literature. 51 CDR H3 structures of this nature are analyzed and we established new sequence-structure rules. These rules contribute to more accurate modeling of the antibody's structure.     

A larger audience,a shorter life

Behavioral Genetics (3rd edition, 1997) Plomin R, DeFries JC, McClearn GE, Rutter M. San Francisco: WH Freeman and Co., 448 pp. £27.95 board; ISBN 0-7167-2824-9