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91.
A locus for binding a mobile water molecule was searched for in the immediate vicinity of the special pair in the reaction center. Using the PROTEUS PC-program (a part of the GRASP package) atomic structures of the reaction centers were analyzed in purple bacteria Rhodopseudomonas viridis and Rhodobacter sphaeroides. In both structures the loci for binding mobile water molecules were found at the distance of about 4.5 Å from the middle of the special pair in the reaction center. The reorientation of a hydrogen atom of this water molecule in the electric field of the excited special pair required energy of no less than 40 MeV that corresponded to predictions of the water-polarization model of trapping of electron excitation which was developed by M. V. Fok and one of the authors of this article. 相似文献
92.
Borisov AIu Vasil'chikov AG Voroshilova VA Danilova TN Zhernakov AI Zhukov VA Koroleva TA Kuznetsova EV Madsen L Mofett M Naumkina TS Nemankin TA Ovchinnikova ES Pavlova ZB Petrova NE Pinaev AG Radutoiu S Rozov SM Rychagova TS Solovov II Stougaard J Topunov AF Weeden NF Tsyganov VE Shtark OIu Tikhonovich IA 《Prikladnaia biokhimiia i mikrobiologiia》2007,43(3):265-271
The review sums up the long experience of the authors and other researchers in studying the genetic system of garden pea (Pisum sativum L.), which controls sthe development of nitrogen-fixing symbiosis and arbuscular mycorrhiza. A justified phenotypic classification of pea mutants is presented. Progress in identifying and cloning symbiotic genes is adequately reflected. The feasibility of using double inoculation as a means of increasing the plant productivity is demonstrated, in which the potential of a tripartite symbiotic system (pea plants-root nodule bacteria-arbuscular mycorrhiza) is mobilized. 相似文献
93.
MATTHEW L. BUFFINGTON SEÁN G. BRADY SHELAH I. MORITA SIMON VAN NOORT 《Systematic Entomology》2012,37(2):287-304
We examine the phylogenetic relationships of Figitidae and discuss host use within this group in light of our own and previously published divergence time data. Our results suggest Figitidae, as currently defined, is not monophyletic. Furthermore, Mikeiinae and Pycnostigminae are sister‐groups, nested adjacent to Thrasorinae, Plectocynipinae and Euceroptrinae. The recovery of Pycnostigminae as sister‐group to Mikeiinae suggests two major patterns of evolution: (i) early Figitidae lineages demonstrate a Gondawanan origin (Plectocynipinae: Neotropical; Mikeiinae and Thrasorinae: Australia; Pycnostigminae: Africa); and (ii) based on host records for Mikeiinae, Thrasorinae and Plectocynipinae, Pycnostigminae are predicted to be parasitic on gall‐inducing Hymenoptera. The phylogenetic position of Parnips (Parnipinae) was unstable, and various analyses were conducted to determine the impact of this uncertainty on both the recovery of other clades and inferred divergence times; when Parnips was excluded from the total evidence analysis, Cynipidae was found to be sister‐group to [Euceroptrinae + (Plectocynipinae (Thrasorinae + (Mikeiinae + Pycnostigminae)))], with low support. Divergence dating analyses using BEAST indicate the stem‐group node of Figitidae to be c. 126 Ma; the dipteran parasitoids (Eucoilinae and Figitinae), were estimated to have a median age of 80 and 88 Ma, respectively; the neuropteran parasitoids (Anacharitinae), were estimated to have a median age of 97 Ma; sternorrhynchan hyperparasitoids (Charipinae), were estimated to have a median age of 110 Ma; the Hymenoptera‐parasitic subfamilies (Euceroptinae, Plectocynipinae, Trasorinae, Mikeiinae, Pycnostigminae, and Parnipinae), ranged in median ages from 48 to 108 Ma. Rapid radiation of Eucoilinae subclades appears chronologically synchronized with the origin of their hosts, Schizophora (Diptera). Overall, the exclusion of Parnips from the BEAST analysis did not result in significant changes to divergence estimates. Finally, though sparsely represented in the analysis, our data suggest Cynipidae have a median age of 54 Ma, which is somewhat older than the age of Quercus spp (30–50 Ma), their most common host. 相似文献
94.
Prenatal maternal psychological distress increases risk for adverse infant outcomes. However, the biological mechanisms underlying this association remain unclear. Prenatal stress can impact fetal epigenetic regulation that could underlie changes in infant stress responses. It has been suggested that maternal glucocorticoids may mediate this epigenetic effect. We examined this hypothesis by determining the impact of maternal cortisol and depressive symptoms during pregnancy on infant NR3C1 and BDNF DNA methylation. Fifty-seven pregnant women were recruited during the second or third trimester. Participants self-reported depressive symptoms and salivary cortisol samples were collected diurnally and in response to a stressor. Buccal swabs for DNA extraction and DNA methylation analysis were collected from each infant at 2 months of age, and mothers were assessed for postnatal depressive symptoms. Prenatal depressive symptoms significantly predicted increased NR3C1 1F DNA methylation in male infants (β = 2.147, P = 0.044). Prenatal depressive symptoms also significantly predicted decreased BDNF IV DNA methylation in both male and female infants (β = −3.244, P = 0.013). No measure of maternal cortisol during pregnancy predicted infant NR3C1 1F or BDNF promoter IV DNA methylation. Our findings highlight the susceptibility of males to changes in NR3C1 DNA methylation and present novel evidence for altered BDNF IV DNA methylation in response to maternal depression during pregnancy. The lack of association between maternal cortisol and infant DNA methylation suggests that effects of maternal depression may not be mediated directly by glucocorticoids. Future studies should consider other potential mediating mechanisms in the link between maternal mood and infant outcomes. 相似文献
95.
The writing of this paper has been driven by a series of remarks made by reviewers of author’s works in several journals. They asserted that the Förster theory of inductive resonance is inapplicable in cases when electronic excitations are delocalized over several molecules, or plainly dismissed the theory as “out of date”. Since this is doubtlessly a question of general importance, this paper offers a detailed analysis of the types of molecular ensembles and conditions where the use of Förster theory is well founded.
相似文献96.
V. A. Zhukov O. Y. Shtark A. Y. Borisov I. A. Tikhonovich 《Russian Journal of Genetics》2009,45(11):1279-1288
Recent data on the plant control of early stages of mutually beneficial (mutualistic) symbioses of legumes, the mechanisms
of perception and transmission of the microsymbiont’s molecular signals in the macrosymbiont’s cells, and induction of the
genetic programs of the development of symbiotic compartments and organs of the plant are summarized. It is demonstrated that
the genetic system of the plant controlling the development of nitrogen-fixing symbiosis of legumes (symbiotic root nodules),
which emerged 70–80 Ma ago, has undoubtedly evolved on the basis of the genetic system controlling the development of the
symbiosis with arbuscular mycorrhizal fungi (which emerged 400–500 Ma ago). Interactions between genes and between gene products,
as well as exchange of molecular signals, form the basis of mutually beneficial (mutualistic) plant-bacterium interactions.
Even in the case of a highly specific nitrogen-fixing symbiosis of legumes (symbiotic nodules), the receptors perceiving the
signal from root-nodule bacteria may function in different ways. The development of arbuscular mycorrhiza and nitrogen-fixing
symbiosis in legumes is a multistep process involving hundreds of genes of both the macro- and microsymbionts. For the symbioses
to develop successfully, these genes should act in a coordinated way in the newly formed superorganismal system. Further studies
are necessary to shed light onto the complexity of the plant genetic control of the development of mutualistic symbioses in
legumes and provide information required for improving their functions in adaptive plant-breeding systems. 相似文献
97.
Abstract. We investigated the phylogeny and taxonomy of the Prenolepis genus‐group, a clade of ants we define within the subfamily Formicinae comprising the genera Euprenolepis, Nylanderia, gen. rev. , Paraparatrechina, gen. rev. & stat. nov. , Paratrechina, Prenolepis and Pseudolasius. We inferred a phylogeny of the Prenolepis genus‐group using DNA sequence data from five genes (CAD, EF1αF1, EF1αF2, wingless and COI) sampled from 50 taxa. Based on the results of this phylogeny the taxonomy of the Prenolepis genus‐group was re‐examined. Paratrechina (broad sense) species segregated into three distinct, robust clades. Paratrechina longicornis represents a distinct lineage, a result consistent with morphological evidence; because this is the type species for the genus, Paratrechina is redefined as a monotypic genus. Two formerly synonymized subgenera, Nylanderia and Paraparatrechina, are raised to generic status in order to provide names for the other two clades. The majority of taxa formerly placed in Paratrechina, 133 species and subspecies, are transferred to Nylanderia, and 28 species and subspecies are transferred to Paraparatrechina. In addition, two species are transferred from Pseudolasius to Paraparatrechina and one species of Pseudolasius is transferred to Nylanderia. A morphological diagnosis for the worker caste of all six genera is provided, with a discussion of the morphological characters used to define each genus. Two genera, Prenolepis and Pseudolasius, were not recovered as monophyletic by the molecular data, and the implications of this result are discussed. A worker‐based key to the genera of the Prenolepis genus‐group is provided. 相似文献
98.
99.
100.
The analysis of whole-mount preparations of synaptonemal complexes (SCs) from surface-spread spermatocytes of A. peninsulae (2n = 48A + 1, 2, ... 12 B) had revealed SCs of 23 autosomal bivalents, sex bivalent XY, axial cores and SCs of the B-chromosomes. The intercellular and interindividual variability of the number of B-chromosomes varied from 1 to 12 per cell. The SCs of autosomal bivalents were shown to have a typical structure. The structure and behaviour of SCs of sex bivalent throughout meiotic prophase I appeared to be similar to those observed in other species of this order. Mainly B-univalents and less frequently B-bivalents containing SCs were found to be formed in meiotic prophase I. The full homologues appear to be rarely seen among B-chromosomes of the East-Asiatic mouse. A tendency of forming clusters of B-univalents near the sex bivalent was found, in addition to B-bivalents with lateral elements, having the form of bi- and tri-stranded elements with rare synaptic fragments. Besides this, the SCs of the autosomes of pachytene cells were found to contain structures resembling the recombination nodules. 相似文献