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61.
Ahmet?E.?KideysEmail author Nuray?Soydemir Elif?Eker Vladimir?Vladymyrov Dmitry?Soloviev Frederic?Melin 《Hydrobiologia》2005,543(1):159-168
Phytoplankton abundance, biomass and species composition of the Caspian Sea were evaluated by using samples collected from the Iranian (southern Caspian Sea) and southern Kazakhstan (eastern Caspian Sea) surface waters in March 2001. A total of 45 taxa were found in the samples (20 diatoms, 17 dinoflagellates and 8 others). Abundance and biomass of diatoms were high at the eastern stations, while dinoflagellates were dominant in terms of both biomass and abundance in the southern region. Average abundance and biomass were 40 000 ± 35 000 cell l−1 and 580 ± 690 μg l−1. The mean biomass value found here for the Middle and southern Caspian Sea in March are difficult to compare with the past due to limited information, but seems higher than previously registered values. Higher chlorophyll values were also apparent from the SeaWIFS images in 2001 compared to those in 1998. This is suggested to be due to decreased grazing of phytoplankton by zooplankton which is voraciously preyed by the recent invasive ctenophore Mnemiopsis leidyi. 相似文献
62.
Halby L Ryabinin VA Sinyakov AN Novopashina DS Venyaminova AG Grokhovsky SL Surovaya AN Gursky GV Boutorine AS 《Journal of biomolecular structure & dynamics》2007,25(1):61-76
Two hairpin hexa(N-methylpyrrole)carboxamide DNA minor groove binders (MGB) were linked together via their N-termini in head-to-head orientation. Complex formation between these bis-MGB conjugates and target DNA has been studied using DNase I footprinting, circular dichroism, thermal dissociation, and molecular modeling. DNase I footprint revealed binding of these conjugates to all the sites of 492 b.p. DNA fragment containing (A/T)(n)X(m)(A/T)(p) sequences, where n>3, p>3; m=1,2; X = A,T,G, or C. Binding affinity depended on the sequence context of the target. CD experiments and molecular modeling showed that oligo(N-methylpyrrole)carboxamide moieties in the complex form two short antiparallel hairpins rather than a long parallel head-to-head hairpin. Binding of bis-MGB also stabilized a target duplex thermodynamically. Sequence specificity of bis-MGB/DNA binding was validated using bis-conjugates of sequence-specific hairpin (N-methylpyrrole)/(N-methylimidazole) carboxamides. In order to increase the size of recognition sequence, the conjugates of bis-MGB with triplex-forming oligonucleotides (TFO) were synthesized and compared to TFO conjugated with single MGB hairpin unit. Bis-MGB-oligonucleotide conjugates also bind to two blocks of three and more A.T/T.A pairs similarly to bis-MGB alone, independently of the oligonucleotide moiety, but with lower affinity. However, the role of TFO in DNA recognition was demonstrated for mono-MGB-TFO conjugate where the binding was detected mainly in the area of the target sequence consisting of both MGB and TFO recognition sites. Basing on the molecular modeling, three-dimensional models of both target DNA/bis-MGB and target DNA/TFO-bis-MGB complexes were built, where bis-MGB forms two antiparallel hairpins. According to the second model, one MGB hairpin is in the minor groove of 5'-adjacent A/T sequence next to the triplex-forming region, whereas the other one occupies the minor groove of the TFO binding polypurine tract. All these data together give a key information for the construction of MGB-MGB and MGB-oligonucleotide conjugates possessing high specificity and affinity for the target double-stranded DNA. 相似文献
63.
Victor A. Sorokin Olga A. Antonova Vladimir A. Valeev 《Journal of inorganic biochemistry》1984,20(4):299-311
The effect ot Cu2+ and Ca2+ ions, on the ultraviolet differential (UVD) spectra of single-stranded poly I was studied and the coordination (Δεb) and conformation (Δεc) conponents of the spectra calculated The comparison of Δεb and the UVD spectrum of protonated IMP leads to the conclusion that N(7) ot inosine-5'-monophosphate (IMP) is a coordinating site tor Ca2+ and Cu2+ ions on the polymer bases. The binding ot Ca2+ and Cu2+ ions causes differently directed displacements of the four absorption bands of poly I, which are observed in the wavenumber range (50-34) × 103 cm−1 The calculation of concentration dependencies tor the association constants (K“) ot Ca2+ and Cu2+ ions binding to poly I bases shows that the binding is cooperative The K“ values for the poly I + Ca2+ complex are two orders of magnitude lower than those for the poly 1 + Cu2+ complex At low ion concentrations, binding to the poly I phosphates predominates and increases the degree of the polynucleotide helicity. At higher concentrations the spectra are mainly affected by the ion binding to bases, which results in melting of the helical parts of poly I At Ca2+ concentrations exceeding 10−3 M light-scattering aggregates are formed. The degree of monomer order in them is close to that observed in multistranded helices of poly I 相似文献
64.
Valeri B. Kozhemyako Galina N. Veremeichik Yuri N. Shkryl Svetlana N. Kovalchuk Vladimir B. Krasokhin Valeri A. Rasskazov Yuri N. Zhuravlev Victor P. Bulgakov Yuri N. Kulchin 《Marine biotechnology (New York, N.Y.)》2010,12(4):403-409
Silicatein genes are known to be involved in siliceous spicule formation in marine sponges. Proteins encoded by these genes,
silicateins, were recently proposed for nanobiotechnological applications. We studied silicatein genes of marine sponges Latrunculia oparinae collected in the west Pacific region, shelf of Kuril Islands. Five silicatein genes, LoSilA1, LoSilA1a, LoSilA2, and LoSilA3 (silicatein-α group), LoSilB (silicatein-β group), and one cathepsin gene, LoCath, were isolated from the sponge L. oparinae for the first time. The deduced amino acid sequence of L. oparinae silicateins showed high-sequence identity with silicateins described previously. LoCath contains the catalytic triad of amino acid residues Cys-His-Asn characteristic for cathepsins as well as motifs typical for
silicateins. A phylogenetic analysis places LoCath between sponge silicateins-β and L-cathepsins suggesting that the LoCath gene represents an intermediate form between silicatein and cathepsin genes. Additionally, we identified, for the first time,
silicatein genes (AcSilA and AcSilB) in nonspicule-forming marine sponge, Acаnthodendrilla sp. The results suggest that silicateins could participate also in the function(s) unrelated to spiculogenesis. 相似文献
65.
Eugene R. Zabarovsky Ilya M. Chumakov Vladimir S. Prassolov Lev L. Kisselev 《Gene》1984,30(1-3):107-111
We have determined the nucleotide sequence of an 841-bp fragment derived from a segment of the human genome previously cloned by Chumakov et al. [Gene 17 (1982) 19–26] and Zabarovsky et al. [Gene 23 (1983) 379–384] and containing regions homologous to the viral mos gene probe. This sequence displays homology with part of the coding region of the human and murine c-mos genes, contains several termination codons, and is interrupted by two Alu-family elements flanked by short direct repeats. Probably, the progenitor of the human c-mos gene was duplicated approximately at the time of mammalian divergence, was converted to a pseudogene, and acquired insertions of two Alu elements. 相似文献
66.
Detecting cryptic species in sympatry and allopatry: analysis of hidden diversity in Polyommatus (Agrodiaetus) butterflies (Lepidoptera: Lycaenidae)
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Vladimir A. Lukhtanov Alexander V. Dantchenko Maria S. Vishnevskaya Alsu F. Saifitdinova 《Biological journal of the Linnean Society. Linnean Society of London》2015,116(2):468-485
Modern multilocus molecular techniques are a powerful tool in the detection and analysis of cryptic taxa. However, its shortcoming is that with allopatric populations it reveals phylogenetic lineages, not biological species. The increasing power of coalescent multilocus analysis leads to the situation in which nearly every geographically isolated or semi‐isolated population can be identified as a lineage and therefore raised to species rank. It leads to artificial taxonomic inflation and as a consequence creates an unnecessary burden on the conservation of biodiversity. To solve this problem, we suggest combining modern lineage delimitation techniques with the biological species concept. We discuss several explicit principles on how genetic markers can be used to detect cryptic entities that have properties of biological species (i.e. of actually or potentially reproductively isolated taxa). Using these principles we rearranged the taxonomy of the butterfly species close to Polyommatus (Agrodiaetus) ripartii. The subgenus Agrodiaetus is a model system in evolutionary research, but its taxonomy is poorly elaborated because, as a rule, most of its species are morphologically poorly differentiated. The taxon P. (A.) valiabadi has been supposed to be one of the few exceptions from this rule due to its accurately distinguishable wing pattern. We discovered that in fact traditionally recognized P. valiabadi is a triplet of cryptic species, strongly differentiated by their karyotypes and mitochondrial haplotypes. 相似文献
67.
Sezgin E Levental I Grzybek M Schwarzmann G Mueller V Honigmann A Belov VN Eggeling C Coskun U Simons K Schwille P 《Biochimica et biophysica acta》2012,1818(7):1777-1784
Several simplified membrane models featuring coexisting liquid disordered (Ld) and ordered (Lo) lipid phases have been developed to mimic the heterogeneous organization of cellular membranes, and thus, aid our understanding of the nature and functional role of ordered lipid-protein nanodomains, termed "rafts". In spite of their greatly reduced complexity, quantitative characterization of local lipid environments using model membranes is not trivial, and the parallels that can be drawn to cellular membranes are not always evident. Similarly, various fluorescently labeled lipid analogs have been used to study membrane organization and function in vitro, although the biological activity of these probes in relation to their native counterparts often remains uncharacterized. This is particularly true for raft-preferring lipids ("raft lipids", e.g. sphingolipids and sterols), whose domain preference is a strict function of their molecular architecture, and is thus susceptible to disruption by fluorescence labeling. Here, we analyze the phase partitioning of a multitude of fluorescent raft lipid analogs in synthetic Giant Unilamellar Vesicles (GUVs) and cell-derived Giant Plasma Membrane Vesicles (GPMVs). We observe complex partitioning behavior dependent on label size, polarity, charge and position, lipid headgroup, and membrane composition. Several of the raft lipid analogs partitioned into the ordered phase in GPMVs, in contrast to fully synthetic GUVs, in which most raft lipid analogs mis-partitioned to the disordered phase. This behavior correlates with the greatly enhanced order difference between coexisting phases in the synthetic system. In addition, not only partitioning, but also ligand binding of the lipids is perturbed upon labeling: while cholera toxin B binds unlabeled GM1 in the Lo phase, it binds fluorescently labeled GM1 exclusively in the Ld phase. Fluorescence correlation spectroscopy (FCS) by stimulated emission depletion (STED) nanoscopy on intact cellular plasma membranes consistently reveals a constant level of confined diffusion for raft lipid analogs that vary greatly in their partitioning behavior, suggesting different physicochemical bases for these phenomena. 相似文献
68.
Folkert Reck Alun Bermingham Johanne Blais Vladimir Capka Taryn Cariaga Anthony Casarez Richard Colvin Charles R. Dean Alex Fekete Wanben Gong Ellie Growcott Hongqiu Guo Adriana K. Jones Cindy Li Fengxia Li Xiaodong Lin Mika Lindvall Sara Lopez Qingming Zhu 《Bioorganic & medicinal chemistry letters》2018,28(4):748-755
Metallo-β-lactamases (MBLs), such as New Delhi metallo-β-lactamase (NDM-1) have spread world-wide and present a serious threat. Expression of MBLs confers resistance in Gram-negative bacteria to all classes of β-lactam antibiotics, with the exception of monobactams, which are intrinsically stable to MBLs. However, existing first generation monobactam drugs like aztreonam have limited clinical utility against MBL-expressing strains because they are impacted by serine β-lactamases (SBLs), which are often co-expressed in clinical isolates. Here, we optimized novel monobactams for stability against SBLs, which led to the identification of LYS228 (compound 31). LYS228 is potent in the presence of all classes of β-lactamases and shows potent activity against carbapenem-resistant isolates of Enterobacteriaceae (CRE). 相似文献
69.
Organ printing, or the layer by layer additive robotic biofabrication of functional three-dimensional tissue and organ constructs using self-assembling tissue spheroid building blocks, is a rapidly emerging technology that promises to transform tissue engineering into a commercially successful biomedical industry. It is increasingly obvious that similar well-established industries implement automated robotic systems on the path to commercial translation and economic success. The use of robotic bioprinters alone however is not sufficient for the development of large industrial scale organ biofabrication. The design and development of a fully integrated organ biofabrication line is imperative for the commercial translation of organ printing technology. This paper presents recent progress and challenges in the development of the essential components of an organ biofabrication line. 相似文献
70.
Valery N Urakov Igor A Valouev Natalia V Kochneva-Pervukhova Anna N Packeiser Alexander Yu Vishnevsky Oleg O Glebov Vladimir N Smirnov Michael D Ter-Avanesyan 《BMC molecular biology》2006,7(1):34-13