共查询到20条相似文献,搜索用时 0 毫秒
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Megan Raby 《Journal of the history of biology》2011,44(1):155-157
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Despite the widespread distribution of Astyanax bockmanni in streams from Upper Paraná River system in central, southeastern, and southern Brazil, just recently, it has been identified
as a distinct Astyanax species. Cytogenetic studies were performed in two populations of this species, revealing conservative features. A. bockmanni shows 2n = 50 chromosomes, a karyotypic formula composed of 10 M + 12SM + 12ST + 16A and multiple Ag-NORs. Eight positive signals
in subtelocentric/acrocentric chromosomes were identified by fluorescent in situ hybridization (FISH) with 18S rDNA probes.
After FISH with 5S rDNA probes, four sites were detected, comprising the interstitial region of a metacentric pair and the
terminal region on long arms of another metracentric pair. Little amounts of constitutive heterochromatin were observed, mainly
distributed at distal region in two chromosomal pairs. Additionally, heterochromatin was also located close to the centromeres
in some chromosomes. No positive signals were detected in the chromosomes of A. bockmanni by FISH with the As-51 satellite DNA probe. The studied species combines a set of characteristics previously identified in
two different Astyanax groups. The chromosomal evolution in the genus Astyanax is discussed. 相似文献
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Xyris irwinii (Xyridaceae), a new species from the cerrado of Goiás, Brazil is described and illustrated. The distribution, phenology, and conservation status of the new species are presented, as well as a comparison of a complex of morphologically related cerrado species. 相似文献
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Miles A. Powell 《Journal of the history of biology》2018,51(3):609-611
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A Gram-negative, non-motile bacterium, designated KSL5401-037T, was isolated from a sewage treatment plant in Gwangju in the Republic of Korea and was characterized using a polyphasic
taxonomic approach. Comparative 16S rRNA gene sequence analysis showed that strain KSL5401-037T belonged to the genus Acinetobacter in the family Moraxellaceae of the Gammaproteobacteria (Brisou and Prevot, 1954). According to a 16S rRNA gene sequence analysis, it was closely related to Acinetobacter johnsonii ATCC 17909T (97.3%), A. bouvetii 4B02T (97.2%), and A. beijerinckii 58aT (96.8%). Chemotaxonomic data revealed that strain KSL5401-037T possesses an ubiquinone system with Q-8 as the predominant compound and C16:0 (19.2%), C18:1 ω9c (19.5%), and summed feature 3 (C16:1
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ω7c, 34.1%) as the predominant cellular fatty acids. The major polar lipids detected in strain KSL5401-037T were diphosphatidylglycerol (DPG) and, phosphatidylethanolamine (PE), followed by phosphatidylglycerol (PG) and moderate
amounts of phosphatidylcholine and phosphatidylserine. The G+C content of the genomic DNA was 41.2–42.1 mol%. Strain KSL5401-037T exhibited relatively low levels of DNA-DNA relatedness with respect to A. johnsonii DSM 6963T (17.7%) and A. bouvetii 4B02T (9.3%). The DNA-DNA relatedness values, biochemical, and physiological characteristics of strain KSL5401-037T strongly support its genotypic and phenotypic differentiation from other recognized type strains of the genus Acinetobacter. Based on these data, strain KSL5401-037T (JCM 17071T =KEMC 5401-037T) should be classified in the genus Acinetobacter as a type strain of novel species, for which the name Acinetobacter kyonggiensis sp. nov. is proposed. 相似文献
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The new taxon Luteoamylascus aculeatus described in this article is proposed to accommodate two collections of a hypogeous ascomycete from central Spain, characterized by a tomentose yellowish peridium, labyrinth-like gleba filled with whitish hyphae, and intensely reacting amyloid asci. ITS, 28S, and RPB2 data suggest that this new taxon is an independent lineage proposed here as the new genus Luteoamylascus. Until now, this lineage was only known from ectomycorrhizal root tips and mitotic spore mats. In phylogenetic analyses, the Luteoamylascus lineage is placed close to the genera Amylascus, Pachyphlodes, and Scabropezia. Morphological data suggest an affinity with Amylascus. 相似文献
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Our work is the first study on the vocal repertoire of one of the babbler species, Elliot’s laughingthrush. Field studies were carried out in Hupingshan Nature Reserve, Hunan Province, China. There are three types of signals in the repertoire: songs, calls (chattering), and duets. Songs and calls are used by both males and females. The song consists of a quiet introduction (short note) and a louder main part (two or three tonal notes). There are up to four song variants in the repertoire of a given pair. All songs can be classified into three types. Types I and II represent songs with the main part consisting of three notes, while type III consists of two notes. Types I and II differ from each other in certain features of the frequency modulation shape of the first two notes. All song types can be used during the spontaneous vocalization of a single bird. However, their usage in other contexts differs. Songs of types I and II are more often uttered during vocal interactions of neighbor males. Songs of type III appear to be characteristic of male–female duets. Chattering (calls) is a continuous series of broadband notes. There are several (two to five) note variants in each series. Chattering can be used both during a male–female interaction and as an alarm call. We found an inverse correlation between (1) the duration of pauses between notes, and (2) the number of note variants (“repertoire size”) in a series. Both parameters probably reflect the internal state of an individual at a given moment. 相似文献
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In the present study, an effort was made to design prolonged release Eudragit nanoparticles of brimonidine tartrate by double
emulsion–solvent evaporation technique for the treatment of open-angle glaucoma. The effect of various formulation variables
like initial drug amount, lecithin proportion, phase volume and pH, secondary emulsifier and polymer proportion were studied.
Various process variables like energy and duration of emulsification, lyophilization on the characteristics of nanoparticles
and in vitro drug release profile were studied. The selected formulations were subjected to in vivo intraocular pressure-lowering efficacy studies by administering aqueous dispersion of nanoparticles into the lower cul de
sac of glaucomatous rabbits. The prepared Eudragit-based nanoparticles were found to have narrow particle size range and improved
drug loading. The investigated process and formulation variables found to have significant effect on the particle size, drug
loading and entrapment efficiency, and in vitro drug release profile of nanoparticles. The selected formulations upon in vivo ocular irritability and tolerability tests were found to be well tolerated with no signs of irritation. In vivo pharmacodynamic efficacy studies revealed that the selected nanoparticle formulations significantly improved the therapy
as area under the ∆IOP vs. time curve [AUC(∆IOP vs.t)] showed several fold increase in intensity and duration of intraocular pressure (IOP) decrease. All the selected nanoparticle
formulations were found to prolong the drug release in vitro and prolong IOP reduction efficacy in vivo, thus rendering them as a potential carrier in developing improved drug delivery systems for the treatment of glaucoma. 相似文献
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The new species Ramaria chocoënsis (Gomphales, Basidiomycota) from Colombian Pacific rainforest is described. Despite the gomphoid habit, the new species is inserted in Ramaria sect. Dendrocladium due to rhizomorph anatomy. In rhizomorphs of members of Ramaria sect. Dendrocladium, as in the new species R. chocoënsis, peculiar, thick-walled, gnarled, sphere-bearing hyphae are found, a feature unknown for any other higher fungi. A short survey of hitherto known rhizomorph features within the Gomphales is given. The possibility of putting the members of Ramaria sect. Dendrocladium in a separate genus is taken into account. It would be advisable to have additional data by screening the anatomy of the rhizomorphs in other species, to more accurately predict the classification of Ramaria chocoënsis sp. nov. 相似文献