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1.
New species Zanclorhynchus chereshnevi sp. n. has been described. The type series of the new species has been sampled along the shores of Prince Edward Islands (46°55′ S 37°58′ E) in the Southern Ocean at the depth of 170 m. The new species differs from the another representative of the genus, Z. spinifer, by weak arming of the first dorsal fin and the head and by the body proportions and coloration.  相似文献   

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The coral species Leptoseris troglodyta sp. n. (Scleractinia, Agariciidae) is described as new to science. It is the first known azooxanthellate shallow-water agariciid and is recorded from the ceilings of caves at 5-35 m depth in West Pacific coral reefs. The corals have monocentric cup-shaped calices. They may become colonial through extramural budding from the basal coenosteum, which may cause adjacent calices to fuse. The size, shape and habitat of Leptoseris troglodyta are unique compared to other Leptoseris species, many of which have been recorded from mesophotic depths. The absence of zooxanthellae indicates that it may survive well in darkness, but endolithic algae in some corals indicate that they may be able to get some light. The presence of menianes on the septal sides, which may help to absorb light at greater depths in zooxanthellate corals, have no obvious adaptive relevance in the new species and could have been inherited from ancestral species that perhaps were zooxanthellate. The new species may be azooxanthellate as derived through the loss of zooxanthellae, which would be a reversal in Leptoseris phylogeny.  相似文献   

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The relationship among the three cellular domains Archaea, Bacteria, and Eukarya has become a central problem in unraveling the tree of life. This relationship can now be studied as the completely sequenced genomes of representatives of these cellular domains become available. We performed a bioinformatic investigation of the Encephalitozoon cuniculi proteome. E. cuniculi has the smallest sequenced eukaryotic genome, 2.9 megabases coding for 1997 proteins. The proteins of E. cuniculi were compared with a previously characterized set of eukaryotic signature proteins (ESPs). ESPs are found in a eukaryotic cell, whether from an animal, a plant, a fungus, or a protozoan, but are not found in the Archaea and the Bacteria. We demonstrated that 85% of the ESPs have significant sequence similarity to proteins in E. cuniculi. Hence, E. cuniculi, a minimal eukaryotic cell that has removed all inessential proteins, still preserves most of the ESPs that make it a member of the Eukarya. The locations and functions of these ESPs point to the earliest history of eukaryotes.Reviewing Editor: Dr. Manyuan Long  相似文献   

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A new variety of Plagiomnium undulatum (Hedw.) T. Kop. var. madeirense T. Kop. & C. Sérgio is described from Madeira Island. The plants present an aquatic ecology and are characterised by broadly and longly decurrent leaves and by large size of laminal cells. This taxon is illustrated and the specimens studied are mapped.  相似文献   

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The extracellular α-amylase from the hyperthermophilic archaeum Pyrococcus furiosus (PFA) is extremely thermostable and of an industrial importance and interest. PFA aggregates and accumulates as insoluble inclusion bodies when expressed as a heterologous protein at a high level in Escherichia coli. In the present study, we investigated the roles of chaperones from P. furiosus in the soluble expression of recombinant PFA in E. coli. The results indicate that co-expression of PFA with the molecular chaperone prefoldin alone significantly increased the soluble expression of PFA. Although, co-expression of other main chaperone components from P. furiosus, such as the small heat shock protein (sHSP) or chaperonin (HSP60), was also able to improve the soluble expression of PFA to a certain extent. Co-expression of chaperonin or sHSP in addition to prefoldin did not further increase the soluble expression of PFA. This finding emphasizes the biotechnological potentials of the molecular chaperone prefoldin from P. furiosus, which may facilitate the production of recombinant PFA.  相似文献   

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The volatile composition of needles from three F1 hard pine hybrids produced by the controlled hybridization and their parental species were researched with gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS) in order to explore the utility of terpenes in hybrid identification (their differentiation from the parental species) as well as confirmation of hybridity. The analysed hybrids were: 1. Pinus nigra J. F. Arnold × Pinus sylvestris L. (= nisy), 2. P. nigra × Pinus densiflora Siebold et Zucc. (= nide) and 3. P. nigra × Pinus thunbergiana Franco (= nith). A total of 55 compounds were identified. All identified compounds were terpenes, except trans-2-hexenal.Three analysed F1 hybrids showed the same qualitative pattern of the needle volatile composition as their parental species. However, there were quantitative differences in several major terpenes. The volatile composition of the needles from the hybrids nisy were equally similar to both parents, the hybrids nide were more similar to the female parent (P. nigra), whereas the hybrids nith were more similar to the male parent (P. thunbergiana). According to the content of germacrene D, as the specific component of P. nigra (female parent of the three analysed F1 hybrids), all hybrids were intermediary in relation to the parental species. The content of Δ-3-carene (the specific component of P. sylvestris) in the hybrids nisy was also intermediary. The hybrids nide had a higher content of thunbergol (specific component of P. densiflora) than the other analysed hybrids. In view of the content of β-pinene, the specific component of P. thunbergiana, the hybrids nith were intermediary to the parental species and that content was considerably higher than in the other analysed hybrids. The intermediary quality of F1 hybrids for these specific components in relation to the parental species confirms their hybrid character.The needle volatile composition analysis as well as the previous morphometric analysis confirm the hybrid character of three F1 hybrids, whose female parent is P. nigra, and male parents are P. sylvestris, P. densiflora, i.e. P. thunbergiana.  相似文献   

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Specimens of a new species of Loricifera, Spinoloricus turbatio gen. et sp. nov., have been collected at the Galápagos Spreading Center (GSC) during the cruise SO 158, which is a part of the MEGAPRINT project. The new genus is positioned in the family Nanaloricidae together with the three already described genera Nanaloricus, Armorloricus and Phoeniciloricus. The postlarvae and adults of Spinoloricus turbatio gen. et sp. nov. are characterized by a mouth cone with eight oral ridges and basally with a cuticular reinforcement named mouth cone pleat; eighth row with 30 whip-like spinoscalids and 30 “alternating” plates; thorax with eight single and seven double trichoscalids, where the single trichoscalids are twice the length of the double ones, and the secondary appendage on the double trichoscalid is smooth whereas the others are serrated; lorica with eight cuticular plates with additional spikes in the anterior corners and intercalary plicae between the plates. Some of these genus-specific characters such as the mouth cone pleat, the “alternating” plates and the intercalary plicae have not been observed in Nanaloricidae before. The Higgins-larvae of Spinoloricus turbatio gen. et sp. nov. are characterized by six rectangular plates in the seventh row with two teeth, an indistinct honeycomb sculpture and long toes with little mucrones. The SO 158 cruise has yielded a minimum of ten new species of Loricifera out of only 42 specimens. These new species belong to two different orders, where one being new to science, and three different families. This result indicates a high diversity of loriciferans at the GSC. Nearly all the collected loriciferans are in a moulting stage, hence there is a new stage inside the present stage. This prolongation of life stages and the occurrence of multiple life stages inside each other are typical of deep-sea loriciferans. Here exemplified by the two postlarvae with adults inside, which is observed for the first time in Nanaloricidae.  相似文献   

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The β-clamp protein and the γ clamp loader complex are essential components of bacterial DNA replication machinery. The β-clamp is a ring-shaped homodimer that encircles DNA and increases the efficiency of replication by providing a binding platform for DNA polymerases and other replication-related proteins. The β-clamp is loaded onto DNA by the five-subunit γ clamp loader complex in a multi-step ATP-dependent process. The initial steps of this process involve the cooperative binding of the β-clamp by the five subunits of ATP-bound clamp loader, which induces or traps an open conformation of the clamp. Remarkably, the δ subunit of the E. coli clamp loader, or even its 140 residue N-terminal domain (called mini-δ), alone can shift conformational equilibrium of the β-clamp towards the open state. Here we report nearly complete backbone and side-chain 1H, 13C and 15N NMR resonance assignments of mini-δ that will facilitate NMR studies of the mechanisms of β-clamp opening and its loading on DNA by the clamp loader.  相似文献   

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The present investigation was undertaken to evaluate the antimicrobial and antioxidant activities of the wild edible mushroom Agaricus lanipes, and also to investigate its cytotoxicity and potential and possible apoptotic effect against the A549 lung cancer cell line in in vitro conditions. Total antioxidant capacity, total phenolic content, total oxidant status, total antioxidant status, lipid hydroperoxides, and total free –SH levels of A. lanipes were found to be 4.55 mg T/g, 14.6 mg GA equivalent/g, 3.10 mg H2O2 equivalent/g, 2.25 mg H2O2 equivalent/g, and 1.90 µmol/g, respectively. The methanolic extract of A. lanipes had relatively strong antimicrobial activity against seven tested microorganism strains. It also had high anti-proliferative potency and strong pro-apoptotic effects, and this mushroom used as a daily nutrient could be a source for new drug developments and treatment in cancer therapies, and could be a guide for studies in this area.  相似文献   

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Prolonged persistence of neuroblast clusters has been revealed in the adult optic lobes of Carabus nemoralis and C. hortensis. These ground beetles were shown to differ considerably from many other holometabolous insects studied, in which the optic anlagen degenerate early in the first half of the pupal stage. It is supposed that long-lasting persistence of the optic anlagen in Carabus reflects the general prolongation of neurogenesis in Coleoptera.  相似文献   

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Skleryk RS  So AK  Espie GS 《Planta》2002,214(4):572-583
We have examined the effect of inorganic and organic carbon nutrition on the physiological expression of HCO3- transport and the CO2-concentrating mechanism (CCM) in the nutritionally versatile cyanobacterium Chlorogloeopsis sp. ATCC 27193. Cells grown under photoautotrophic conditions in the presence of limiting or replete levels of inorganic carbon (Ci), or grown under mixotrophic (light) or chemoheterotrophic (dark) conditions in the presence of sucrose retained both active CO2 and Na(+)-independent HCO3- transport activity. However, two distinct effects on the kinetic properties of HCO3- transport were observed, which segregated on the basis of phototrophic and chemoheterotrophic growth in the dark. In the former, the apparent substrate affinity of the HCO3- transport system (K0.5) varied (12-fold) in response to the growth Ci or mixotrophy while the maximum rate of HCO3- transport was approximately constant. In the latter case, the K0.5 value was unchanged from the starting value (35 microM) of Ci-limited photoautotrophic cells used to initiate the dark-grown cultures, but transport capacity declined 3-fold. Modulation of the K0.5 (HCO3- transport) value required light. Cellular carboxysome content was unaffected by growth under any of the regimes employed and these structures were the predominant location of ribulose-1,5-bisphosphate carboxylase/oxygenase, as indicated by immunogold electron microscopy. Mixotrophic and chemoheterotrophic growth resulted in a diminished ability to concentrate Ci internally and a reduction in Ci accumulation ratios at low external Ci concentrations. The relationship between photosynthetic carbon fixation and the internal Ci pool varied by 2-fold, with high-Ci-grown cells being the most efficient and mixotrophically grown cells the least, indicating that there was limited capacity to modulate this relationship in response to changes in carbon nutrition. Within broad limits this relationship appeared to be a fixed trait of the strain and an important factor in determining growth rate.  相似文献   

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Brancelj  Anton 《Hydrobiologia》2000,437(1-3):235-239
Parastenocaris andreji n. sp. was found in ground water in a northwestern part of Slovenia (southern part of Central Europe). Two adult females of the new species were filtered out of 20 000 l of water during examination of an aquifer for water supply. The bore well was 10 m deep. The aquifer is fed by rainwater and probably only occasionally from a nearby alpine river Sava. The new species differs markedly from other known species of the genus by shape and armature of furcal rami, very long and slim maxillae and some characters on endopodites P2–P5. The closest related species are probably Parastenocaris nolliKiefer, 1938 with subspecies P. nolli alpinaKiefer, 1960, P. gertrudae Kiefer, 1968 and P. austriacaKiefer, 1976.  相似文献   

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A female of Foxtosognus rarus gen. n., sp. n., a new genus and species of copepods, is described from the abyss of the Kuril-Kamchatka Trench. The new genus is placed in the family Arctokonstantinidae, whose diagnosis is emended and supplemented with the following characters: mandibular basis with one to two setae; mandibular endopod one without setae; maxillular distal basal endite plus endopod with two to four setae or without setae. The features that distinguish Foxtosognusgen. n. from other representatives of this family are as follows: mandibular palp with a long endopod segment one, endopod segment two with seven setae, and exopod segment five with two setae; maxillula with distal basal endite lacking setae and separated from endopod bearing three setae; maxillular precoxal arthrite with seven to eight setae and exopod with four setae; maxilliped syncoxa without setae on precoxal endites and endopod of three segments. The genera Sognocalanus and Foxtonia earlier included in the Spinocalanidae are herein transferred to the Arctokonstantinidae.  相似文献   

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