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1.
2.
Cannibalism is known to be a significant source of natural mortality of young North-east Arctic (NEA) cod. Cannibalism data, starting from 1984, have been used in NEA cod stock assessments since 1995, which has led to inconsistency in the cod abundance time series from 1946 to the present. To address this inconsistency, this study estimates the cannibalism-induced mortality (M2) of NEA cod at age 3–5 for the period 1946–1983. Combined qualitative and quantitative cod stomach content data for 1984–2010 were used to make the M2 estimations for age groups 3–5 (ICES 2014), then different factors including SSB were used to examine which covariates explained variability in M2 and thus make predictions for 1946–1983. The level of cannibalism was estimated to be high in the 1950s – early1960s. VPA-based assessment was run using these estimated M2 values. As a result, numbers of cod eaten by their conspecifics in the historical period and new increased recruitment estimates at age 3 were computed. The main factors affecting cannibalism appeared to be young cod abundance, total stock biomass (TSB) of large cod, and capelin total stock biomass (which represents an alternative prey). The problems involved in using the new recruitment time series in fishery management are discussed. The methodology presented here represents a generic approach to extending predation mortalities back in time to improve historical stock estimates. 相似文献
3.
B A Tikunov 《Biokhimii?a (Moscow, Russia)》1990,55(5):822-828
The effect of magnesium ions on the two-stage kinetics of superprecipitation (SPP) and ATP activity of natural skeletal muscle actomyosin was studied. It was found that the changes in the ratios of two independent steps of SPP and ATPase activity are mainly induced by the Mg-ATP2- complex, but not by free Mg2+. These changes in the kinetics of SPP and ATPase are regarded as being due to the shift in the dynamic equilibrium between the two types of the actomyosin complexes in solution, each of which is characterized by different reaction mechanisms. The role of the Mg-ATP2(-)-induced alteration of at least two structural-and-functional states of actomyosin in muscle contractibility is discussed. 相似文献
4.
In somatic hybrids between tumourous Nicotiana tabacum (B6S3) and normal mesophyll Atropa belladonna cells, the following traits, directly or indirectly connected with T-DNA gene expression and tumourous growth, were analysed: lysopine dehydrogenase activity (LpDH), shoot suppression, root suppression, ability to grow on media with D-lactose as a sole carbon source and resistance to 2-aminoethylcysteine, 5-bromodeoxyuridine and 5-methyltryptophan. Dominant (semidominant) expression was observed for all but one trait studied, e.g. shoot suppression which behaved as a recessive character.Abbreviations LS-H
Linsmaier and Skoog (1965) hormone-free medium
- NAA
Naphtaleneacetic acid
- BAP
6-Benzylaminopurine
- 2,4-D
2,4-Dichlorophenoxyacetic acid
- 5-BUdR
5-Bromodeoxyuridine
- 2-AEC
2-Aminoethylcysteine
- 5-MT
5-Methyltryptophan 相似文献
5.
Dmitry I. Nurminsky Yury Ya. Shevelyov Sergei V. Nuzhdin Vladimir A. Gvozdev 《Chromosoma》1994,103(4):277-285
The 60 kb repeats located in the distal heterochromatin of the X chromosome of Drosophila melanogaster were cloned in overlapping cosmids. These regions, designated as SCLRs, comprised the following types of repeated elements Stellate genes, which are known to be involved in spermatogenesis; copia-like retrotransposons; LINE elements, including amplified Type rDNA insertions; and rDNA fragments. The following steps in SCLR formation were hypothesized: insertion of mobile elements into the rDNA and Stellate gene clusters: internal tandem duplication events; recombination between the rDNA cluster and Stellate tandem repeat; and amplification of the whole SCLR structure. There are about nine SCLR copies per haploid genome, but there is approximately a twofold variation in copy number between fly stocks. The SCLR copy number differences between closely related stocks are suggested to be the result of unequal sister chromatid exchange (USCE). The restricted variation in SCLR copy number between unrelated stocks and the absence of chromosomes free of SCLRs suggests that natural selection is active in copy number maintenance. 相似文献
6.
Elena Driomina Igor Polnikov Victor Sharov Ofelia Azizova Yury Vladimirov 《Free radical research》1994,20(5):279-288
A chemiluminescence (CL) flash kinetics on the addition of Fe2+ ions into oxidized low density lipoprotein (LDL) suspension has been studied. LDL oxidation was carried out at 37°C without and in the presence of 5 or 50 μM of Cu.2+ It has been found that under certain experimental conditions (the addition of excess iron ions, more than 1 mM) the amplitude of CL flash depended almost linearly (1) on the concentration of oxidized LDL and (2) on the extent of LDL oxidation measured as diene conjugates (DC) and 2-thiobarbituric acid-reactive substance (TBARS) accumulation. The corresponding correlation coefficients were: for TBARS - 0.94 and for DC - 0.97, in the case of LDL autooxidation; 0.72 and 0.98, in the case of copper-induced LDL oxidation. A sensitivity of the CL method was shown to be significantly enhanced (by more than two orders) in the presence of CL sensitizer - 2, 3,5, 6-lH,4H-tetrahydro-9-(2' -benzoimidazolyl)-quinolizin-(9, 9a, 1 -gh)coumarin. 相似文献
7.
Svetlana V. Shilova Grigory M. Mirgaleev Ksenia A. Romanova Yury G. Galyametdinov 《Biopolymers》2023,114(10):e23555
This work reports synthesis of pH-responsive alginate/chitosan hydrogel spheres with the average diameter of 2.0 ± 0.05 mm, which contain cefotaxime that is an antibiotic of the cefalosporine group. The spheres provided the cefotaxime encapsulation efficiency of 95 ± 1%. An in vitro release of cefotaxime from the spheres in the media that simulate human biological fluids in peroral delivery conditions was found to be a pH-dependent process. The analysis of cefotaxime release kinetics by the Korsmeyer–Peppas model revealed a non-Fickian mechanism of its diffusion, which may be related to intermolecular interactions occurring between the antibiotic and chitosan. Conductometry, UV spectroscopy, and IR spectroscopy were used to study complexation of chitosan with cefotaxime in aqueous media with varied pH, characterize the composition of the complexes, and calculate their stability constants. The composition of the cefotaxime–chitosan complexes was found to correspond to the 1.0:4.0 and 1.0:2.0 molar ratios of the components at pH 2.0 and 5.6, respectively. Quantum chemical modeling was used to evaluate energy characteristics of chitosan–cefotaxime complexation considering the influence of a solvent. 相似文献
8.
Deletion analysis of the SUP35 gene of the yeast Saccharomyces cerevisiae reveals two non-overlapping functional regions in the encoded protein 总被引:13,自引:0,他引:13
Michael D. Ter-Avanesyan Vitaly V. Kushnirov Adilya R. Dagkesamanskaya Svetlana A. Didichenko Yury O. Chernoff Sergey G. Inge-Vechtomov Vladimir N. Smirnov 《Molecular microbiology》1993,7(5):683-692
SUP35is an omnipotent suppressor gene of Saccharomyces cerevisiae coding for a protein consisting of a C-terminal part similar to the elongation factor EF-1α and a unique N-terminal sequence of 253 amino acids. Twelve truncated versions of the SUP35 gene were generated by the deletion of fragments internal to the coding sequence. Functional studies of these deletion mutants showed that: (i) only the EF-1α-like C-terminal part of the Sup35 protein is essential for the cell viability; (ii) overexpression of either the N-terminal part of the Sup35 protein or the full-length Sup35 protein decreases translational fidelity, resulting in omnipotent suppression and reduced growth of [psi+] strains; (iii) expression of the C-terminal part of the Sup35 protein generates an antisuppressor phenotype; and (iv) both the N- or C-terminal segments of the Sup35 protein can bind to 80S ribosomes. Thus, the data obtained define two domains within the Sup35 protein which are responsible for different functions. 相似文献
9.
Raisa P. Gorshkova Natalia I. Korchagina Tatianna A. Medonova Elena N. Kalmykova Natalia N. Besednova Yury S. Ovodov 《Carbohydrate research》1980,84(2):237-243
Lipopolysaccharides (LPS) from various strains of Yersinia pseudotuberculosis type V have been isolated and characterised. Differences in sugar composition and serological activity of LPS from various strains within the same subtype of Y. pseudotuberculosis have been revealed. 相似文献
10.
Makarova Kira S.; Mazin Alexander V.; Wolf Yury I.; Soloviev Victor V. 《Bioinformatics (Oxford, England)》1992,8(5):425-431
A computer system DIROM for oligonucleotide-directed mutagenesisand artificial gene design has been designed for better experimentalplanning and control. DIROM permits searching for optimal oligonucleotideswith respect to certain important parameters, namely sufficientenergy of oligonucleotide-target hybridization, the secondarystructure of oligonuc-tide and target DNA, the presence of alternatebinding sites in the target DNA and terminal G/C pairs. It canalso be used to plan polymerase chain reaction experiments,for optimal primer selection, in sequencing, etc. DIROM enablesone to search for both existing and potential restriction sites,to perform vector + target sequence construction. The systemconsists of a set of original algorithms that formalize theempirical knowledge of oligonucleotide action as primers. 相似文献