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Yu Wang Douglas C. Goodwin 《Biochimica et Biophysica Acta - Proteins and Proteomics》2013,1834(1):362-371
Catalase–peroxidases (KatGs) have two peroxidase-like domains. The N-terminal domain contains the heme-dependent, bifunctional active site. Though the C-terminal domain lacks the ability to bind heme or directly catalyze any reaction, it has been proposed to serve as a platform to direct the folding of the N-terminal domain. Toward such a purpose, its I′-helix is highly conserved and appears at the interface between the two domains. Single and multiple substitution variants targeting highly conserved residues of the I′-helix were generated for intact KatG as well as the stand-alone C-terminal domain (KatGC). Single variants of intact KatG produced only subtle variations in spectroscopic and catalytic properties of the enzyme. However, the double and quadruple variants showed substantial increases in hexa-coordinate low-spin heme and diminished enzyme activity, similar to that observed for the N-terminal domain on its own (KatGN). The analogous variants of KatGC showed a much more profound loss of function as evaluated by their ability to return KatGN to its active conformation. All of the single variants showed a substantial decrease in the rate and extent of KatGN reactivation, but with two substitutions, KatGC completely lost its capacity for the reactivation of KatGN. These results suggest that the I′-helix is central to direct structural adjustments in the adjacent N-terminal domain and supports the hypothesis that the C-terminal domain serves as a platform to direct N-terminal domain conformation and bifunctionality. 相似文献
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《Comptes Rendus Palevol》2014,13(2):65-71
A new genus and species, Cryptohelops menaticus gen. et sp. n., are described from the Palaeocene of Menat (France). The new genus belongs to the subtribe Helopina of the tribe Helopini (subfamily Tenebrioninae of Tenebrionidae) based on the coarse and dense punctation of the hypomera, shape of the prosternum and metepisterna, a similar appearance to the native genera Helops and Stenohelops and the structure of the epipleura. The new genus also resembles Raiboscelis and Entomogonus by having the protibiae excised along the base of the inner side. The new genus is the oldest representative of the tribe Helopini. Four species of Helops sensu lato previously described from the Oligocene (H. wetteravicus K. Heyden et L. Heyden, 1865) and Miocene (H. atticus Redtenbacher in Ungern, 1867; H. meissneri Heer, 1847 and H. molassicus Heer, 1883) lack important diagnostic characters and should be regarded as members of the tribe Helopini with uncertain generic attribution. 相似文献
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Sphyrion lumpi is a sexually dimorphic, parasitic copepod which causes significant losses in fisheries in the North Atlantic. Studies involving both light and scanning electron microscopy revealed important details of the external morphology of both sexes that are discussed in relation to other members of the family Sphyriidae. Conclusions are drawn regarding the life cycle of S. lumpi. The present finding of this parasite on Urophycis tenuis constitutes a new host record. 相似文献
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The genus Planinasus Cresson is revised and includes 18 extant and one fossil species. We clarify the status of the three previously described species and describe 15 new species as follows (type locality in parenthesis): Planinasus aenigmaticus (Colombia. Bogota: Bogota (04°35.8''N, 74°08.8''W)), Planinasus neotropicus (Panama. Canal Zone: Barro Colorado Island (09°09.1''N, 79°50.8''W)), Planinasus kotrbae (Ecuador. Orellana: Rio Tiputini Biodiversity Station (0°38.2''S, 76°08.9''W)), Planinasus miradorus (Brazil. Maranhão: Parque Estadual Mirador, Base da Geraldina (06°22.2''S, 44°21.8''W)), Planinasus tobagoensis (Trinidad and Tobago. Tobago. St. John: Parlatuvier (11°17.9''N, 60°39''W)), Planinasus xanthops (Ecuador. Orellana: Rio Tiputini Biodiversity Station (0°38.2''S, 76°8.9''W)), Planinasus argentifacies (Peru. Madre de Dios: Río Manu, Pakitza (11°56.6''S, 71°16.9''W; 250 m)), Planinasus insulanus (Dominican Republic. La Vega: near Jarabacoa, Salto Guasara (19°04.4''N, 70°42.1''W, 680 m)), Planinasus nigritarsus (Guyana. Conservation of Ecological Interactions and Biotic Associations (CEIBA; ca. 40 km S Georgetown; 06°29.9''N, 58°13.1''W)), Planinasus atriclypeus (Brazil. Rio de Janeiro: Rio de Janeiro, Floresta da Tijuca (22°57.6''S, 43°16.4''W)), Planinasus atrifrons (Bolivia. Santa Cruz: Ichilo, Buena Vista (4-6 km SSE; Hotel Flora y Fauna; 17°29.95''S, 63°33.15''W; 4-500 m)), P. flavicoxalis (West Indies. Dominica. St. David: 1.6 km N of junction of roads to Rosalie and Castle Bruce (15°23.8''N, 61°18.6''W)), Planinasus mcalpineorum (Mexico. Chiapas: Cacahoatan (7 km N; 15°04.1''N, 92°07.4''W)), Planinasus nigrifacies (Brazil. São Paulo: Mogi das Cruzes, Serra do Itapeti (23°31.5''S, 46°11.2''W)), Planinasus obscuripennis (Peru. Madre de Dios: Río Manu, Erika (near Salvación; 12°50.7''S, 71°23.3''W; 550 m)). In addition to external characters, we also describe and illustrate structures of the male terminalia and for Planinasus kotrbae
sp. n., the internal female reproductive organs. Detailed locality data and distribution maps for all species are provided. For perspective and to facilitate genus-group and species-group recognition, the family Periscelididae and subfamily Stenomicrinae are diagnosed and for the latter, a key to included genera is provided. 相似文献
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Konrad Ocalewicz Henryk Kuzminski Konrad Pomianowski Stefan Dobosz 《Reproductive biology》2013,13(2):105-112
Failure of interspecific androgenesis between brook charr (Salvelinus fontinalis, Mitchill 1814) and Arctic charr (Salvelinus alpinus, L.) has been attributed to the conflict between the egg cytoplasm of one species and the sperm nucleus of the other species. To overcome this incompatibility, sperm derived from the brook charr × Arctic charr hybrid male was used to induce androgenetic development in eggs originating from the parental species as well as their hybrids. The eggs were subjected to 420 Gy of X-radiation to damage the maternal nuclear DNA and inseminated with untreated sperm. Haploid zygotes were exposed to high hydrostatic pressure shock (7000 psi for 4 min), which was applied 420 min after insemination to inhibit the first cell cleavage and recover the diploid state of the zygote. The androgenetic diploid offspring that hatched from the brook charr, the Arctic charr and the hybrids eggs had survival rates of 4.7 ± 0.6%, 1.2 ± 0.4% and 16.8 ± 0.5%, respectively. Drastic mortality among the hatched androgenetic individuals was observed within the first five months of rearing. Cytogenetic analysis of the androgenetic progenies exhibited residues of the irradiated maternal nuclear genome in the form of radiation-induced chromosome fragments in 47% of the specimens that were examined. Interactions between the egg cytoplasm and the sperm nucleus, the low quality of the gametes, the expression of homozygous paternal lethal alleles and the incomplete inactivation of the maternal chromosomes were identified as factors responsible for the large mortality among androgenetic embryos and hatchlings. 相似文献
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《International Journal of Insect Morphology and Embryology》1997,26(2):139-147
The present work reports on a neuroanatomical study of the butterfly Pararge aegeria (Lepidoptera : Satyridae) focusing on the lamina ganglionaris underlying two different regions of the retina of the compound eye: the dorsal rim area and the large dorsal region. No differences between both lamina regions, concerning the structure of the cartridges and the morphology of the identified neurons, could be detected. After passing the basement membrane, the visual cell axons are organized in retinotopic bundles (pseudocartridges), in which the axons of the 9 visual cells (V1 and 5, D2, 4, 6, 8, H3 and 7, B9) are arranged in the same way as in the retina. In the pseudocartridge there are no synaptic contacts. Before entering the lamina cartridge, the bundles rotate 90 °. The cartridges are joined by the fibres of 4 monopolar cells (L1, L2, L3 and L4), which could be identified and located inside the lamina cartridges in serial EM-sections. Golgi impregnations revealed the morphology of these fibres. Thus, the regional specialization of the retina (dorsal rim area and large dorsal region) does not seem to be reflected at the level of the first visual neuropil. Additionally, the cartridges of both lamina regions were investigated qualitatively for synaptic contacts among fibres. In addition to monadic chemical synapses and multiple contact synapses with presynaptic ribbons, cell contacts are also facilitated by invaginations and bridges. These cellular interactions and their functional implications are discussed. 相似文献
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Gitte Petersen Ole Seberg Argelia Cuenca Dennis W. Stevenson Marcela Thadeo Jerrold I. Davis Sean Graham T. Gregory Ross 《Cladistics : the international journal of the Willi Hennig Society》2016,32(2):141-159
A phylogenetic analysis of the early branching lineages of the monocotyledons is performed using data from two plastid genes (rbcL and matK), five mitochondrial genes (atp1, ccmB, cob, mttB and nad5) and morphology. The complete matrix includes 93 terminals representing Acorus, the 14 families currently recognized within Alismatales, and numerous lineages of monocotyledons and other angiosperms. Total evidence analysis results in an almost completely resolved strict consensus tree, but all data partitions, genomic as well as morphological, are incongruent. The effects of RNA editing and potentially processed paralogous sequences are explored and discussed. Despite a decrease in incongruence length differences after exclusion of edited sites, the major data partitions remain significantly incongruent. The 14 families of Alismatales are all found to be monophyletic, but Acorus is found to be included in Alismatales rather than being the sister group to all other monocotyledons. The placement is strongly supported by the mitochondrial data, atp1 in particular, but it cannot be explained as an artifact caused by patterns of editing or by sampling of processed paralogues. 相似文献
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Jin Zhao Peng Jiang Zhengyi Liu Jinfeng Wang Yulin Cui Song Qin 《Journal of applied phycology》2011,23(2):227-233
Ulva (Enteromorpha) prolifera, widely distributed from the intertidal to the upper subtidal zones around the world, was the dominant species of the massive
green tides in the Yellow Sea in the summers of 2007, 2008, and 2009. However, little is known about its intra-species genetic
diversity. In this study, six attached and seven floating U. prolifera samples collected from different sites distributed from the north of the Yellow Sea to the south of the East China Sea were
taken in inter-simple sequence repeat (ISSR) analysis. Based on the results of the 90 polymorphic bands from four ISSR primers,
the genetic diversity level of the floating samples (H = 0.1663, I = 0.2608) was found to be lower than that of the attached samples (H = 0.2105, I = 0.3346). Unweighted pair-group mean analysis (UPGMA) and principal coordinate analysis (PCoA) suggested that floating U. prolifera samples in the Yellow Sea from 2007 to 2009 had a close genetic relationship, and the floating samples were separated from
the attached samples. Genetic differentiation and limited gene flow among attached U. prolifera populations were indicated by analysis of molecular variance. 相似文献
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Qualitative data are presented on the diet of juvenile chum salmon Oncorhynchus keta released from the Ryazanovka experimental fish hatchery farm situated in the south of Primor’e Territory. The stomach fullness,
frequency of occurrence of food items, their average weight value, and selectivity are estimated. Food spectra of chum salmon
juveniles during downstream migration comprised representatives of 51 taxa of bottom freshwater invertebrates and terrestrial
insects. The bulk of the diet consisted of larvae of aquatic insects—chironomids, other Diptera, and mayflies. Their diversity
increased with the growth of fry. Fry of chum salmon had a wide spectrum of feeding preference, favorite food items were larvae
and pupae of chironomids. 相似文献
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Alexandru Solomon Vlad Codrea Márton Venczel Mihai Dumbravă Thierry Smith 《Journal of Mammalian Evolution》2016,23(4):319-335
The so-called “Ha?eg Island” (Transylvania, Romania) is well known for its rich and peculiar Late Cretaceous vertebrate assemblages, including dwarf dinosaurs, first reported at the end of the 19th century. Besides dinosaurs, other important members of the “Ha?eg Island” terrestrial ecosystems were the multituberculate mammals. Late Cretaceous (Maastrichtian) multituberculates are extremely rare in Europe, being known exclusively from the “Ha?eg Island.” Two genera are reported from this area: Kogaionon, with the single species K. ungureanui, and Barbatodon, with two species: B. transylvanicus and B. oardaensis. Both genera belong to the European endemic family Kogaionidae. We report herein new remains of B. transylvanicus from the Maastrichtian locality of Pui (Hunedoara District) in the Ha?eg Basin, including the most complete dentaries found to date with complete cheek teeth rows. Intraspecific variability of this species in dentary shape, tooth morphology, and size difference is highlighted. 相似文献
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Airoldi M Gennaro G Giomini M Giuliani AM Giustini M 《Journal of biomolecular structure & dynamics》2011,29(3):585-594
When the model polynucleotide poly(dG-dC)?poly(dG-dC) [polyGC] is titrated with a strong acid (HCl) in unbuffered aqueous solutions containing the chlorides of the alkali metals in the concentration range 0.010?M-0.600?M, two transitions in the absorbance vs. pH plots are evidenced, characterized by the constants pK(a(?)) and pK(a(?)). The limiting values at infinite saline concentrations of these two constants, namely pK(∞)(a(?)) and pK(∞)(a(?)) obtained making use of the "one site saturation constant" equation or, in turn, of the double logarithmic plot: pK(a) vs. log([salt]?1), exhibit a clear dependence on the nature of the cations. The effects of the different alkali cations on the pK(∞)(a) values follow the Hofmeister series. In fact, the pK(∞)(a(?)) and the pK(∞)(a(?)) values are smaller for Li+ and Na+ than for Rb+ and Cs+, with K+ at the border between the two, showing that the transitions require higher concentrations of protons to occur in the presence of high concentrations of the cosmotropic ions. 相似文献
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Two new species, Mirovia asiatica sp. nov. and Mirovia kazachstanica sp. nov., are described from the Lower Jurassic of Mangyshlak (western Kazakhstan). Representatives of Mirovia Reymanówna are for the first time found in the Lower Jurassic and for the first time in Central Asia. A new combination,
M. eximia (Gordenko), comb. nov., is proposed. The morphology of stomatal guard cells is described in detail, based on examination
of cross sections of leaves. 相似文献
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Héctor Rodríguez-Pérez Margarita Florencio Carola Gómez-Rodríguez Andy J. Green Carmen Díaz-Paniagua Laura Serrano 《Hydrobiologia》2009,634(1):209-217
We have detected the presence of the North American native corixid Trichocorixa verticalis verticalis (Fieber, 1851) in Doñana wetlands (SW Spain). We have collected data from different research projects done in the area during the period of 2001–2007. We have sampled 134 different sites in Doñana and we found the exotic corixid in 66 occasions. We have found two reproductive populations that might act as sources for the colonization of other waterbodies in the area. When reproduction occurred T. v. verticalis outcompeted native corixids. Its presence out of the waterbodies where we detected reproduction was in small numbers and probably due to vagrant individuals. 相似文献
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It has been shown in a previous paper (8) that the prime product of reassociation of related DNA sequences under open experimental conditions are mismatched duplexes which undergo maturation upon further incubation. Due to this feature, the Tm value of the duplexes of a large number of DNAs is strongly dependent on the Cot value. Here we present data showing that the Tm of the duplexes of such type of DNAs depends also on the concentration of DNA in the range of one and the same Cot value. The significance of this finding in studying the taxonomic relationship by DNA-DNA hybridisation is discussed.Abbreviations Co =
initial concentration of single-stranded DNA in moles of nucleotides per liter
- t =
time of incubation in seconds
- Cot =
the product of Co and t (mol. sec. 11)
- PB =
an equimolar mixture of NaH2PO4 and Na2HPO4, pH 6.8
- HAP =
hydroxyapatite
- Ti =
incubation temperature
- Tm =
melting temperature
- Te =
elution temperature, i.e. the temperature at which one half of the DNA is eluted as single strands by HAP-thermal chromatography 相似文献
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A taxonomic review of seven species of Diplocheila of the Far East of Russia and adjacent lands is given. Three species are known from the Russian Far East, two of which, D. zeelandica Redt. and D. minima Jedl., are recorded from Russia for the first time. A key to the East Asian species is presented. Composition and diagnoses of subgenera are discussed. The subgenus Submera Habu is restored. 相似文献