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1.
Spring arrival response to climate change in birds: a case study from eastern Europe 总被引:3,自引:3,他引:0
Mecislovas Zalakevicius Galina Bartkeviciene Liutauras Raudonikis Justinas Janulaitis 《Journal of Ornithology》2006,147(2):326-343
This paper analyses the dependence of the first spring arrival dates of short/medium- and long-distance migrant bird species
on climate warming in eastern Europe. The timing of arrival of the selected species at the observation site correlates with
the North Atlantic Oscillation (NAO) index, air temperature, atmospheric pressure, precipitation and wind characteristics.
A positive correlation of fluctuations in winter and spring air temperatures with variations in the NAO index has been established
in eastern Europe. Positive winter NAO index values are related to earlier spring arrival of birds in the eastern Baltic region
and vice versa—arrival is late when the NAO index is negative. The impact of climate warming on the bird’s life cycle depends
on local or regional climate characteristics. We tested the hypothesis that differences in climate indices between North Africa
and Europe can influence the timing of spring arrival. Our results support the hypothesis that differences in first spring
arrival dates between European populations occur after individuals cross the Sahara. We assume that the endogenous programme
of migration control in short/medium-distance migrants synchronises with the changing environment on their wintering grounds
and along their migration routes, whereas in long-distance migrants it is rather with environmental changes in the second
part of their migratory route in Europe. Our results strongly indicate that the mechanism of dynamic balance in the interaction
between the endogenous regulatory programme and environmental factors determines the pattern of spring arrival, as well as
migration timing. 相似文献
2.
FspAI, a unique type II restriction endonuclease that recognizes the octanucleotide sequence 5′-RTGC↓GCAY-3′ 下载免费PDF全文
A. Kesminiene Z. Maneliene J. Vitkute M. Petruyte A. Janulaitis 《Nucleic acids research》2001,29(24):e120
A new type II restriction endonuclease designated FspAI has been partially purified from a Flexibacter species Tv-m21K. FspAI recognizes the octanucleotide sequence 5′-RTGC↓GCAY-3′ and cleaves it in the center generating blunt-ended DNA fragments. 相似文献
3.
Phasmids as effective and simple tools for construction and analysis of gene libraries 总被引:1,自引:0,他引:1
N K Yankovsky N O Fonstein MYuLashina SYu Bukanov N V Yakubovich L M Ermakova B A Rebentish A A Janulaitis V G Debabov 《Gene》1989,81(2):203-210
Phasmid lambda pMYF131, a hybrid of phage lambda vectors and plasmid pUC19, was constructed. The phasmid and its derivatives were shown to be efficient vectors for construction and analysis of gene libraries in Escherichia coli cells. The lambda pMYF131 DNA molecule contains all the genes and regions essential for phage lytic development. The plasmid cannot be packaged either in the monomeric or the oligomeric form due to its specific length. Elongation of the DNA molecule by ligation with fragments of foreign DNA can make it packageable and this is easily detected by plaque formation. Hence, the procedures used to construct genomic libraries can be simplified by selection of only recombinant DNA molecules just at the time and on the basis of their packaging in vitro. The output of recombinant clones per vector molecule was several times higher for vector lambda pMYF131, compared to phage vector lambda L47.1AB, and attained 3 x 10(6) clones per micrograms DNA. Vector and recombinant phasmids can be obtained in large quantities in plasmid form. lambda pMYF131 contains nine unique restriction sites which allow the cloning of DNA fragments with blunt ends and of fragments with various types of cohesive ends, obtained by digestion with 14 prototype restriction enzymes. The maximal size of the cloned DNA fragments is approx. 20 kb for lambda pMYF131. Phasmid vectors were used to construct libraries of bovine, pig and quail genomes, and genomic libraries of 17 species of bacteria. Application of suitable methods allowed the identification 13 individual genes within these libraries. 相似文献
4.
Sequence motifs characteristic of DNA[cytosine-N4]methyltransferases: similarity to adenine and cytosine-C5 DNA-methylases 总被引:43,自引:31,他引:12 下载免费PDF全文
S Klimasauskas A Timinskas S Menkevicius D Butkienè V Butkus A Janulaitis 《Nucleic acids research》1989,17(23):9823-9832
The sequences coding for DNA[cytosine-N4]methyltransferases MvaI (from Micrococcus varians RFL19) and Cfr9I (from Citrobacter freundii RFL9) have been determined. The predicted methylases are proteins of 454 and 300 amino acids, respectively. Primary structure comparison of M.Cfr9I and another m4C-forming methylase, M.Pvu II, revealed extended regions of homology. The sequence comparison of the three DNA[cytosine-N4]-methylases using originally developed software revealed two conserved patterns, DPF-GSGT and TSPPY, which were found similar also to those of adenine and DNA[cytosine-C5]-methylases. These data provided a basis for global alignment and classification of DNA-methylase sequences. Structural considerations led us to suggest that the first region could be the binding site of AdoMet, while the second is thought to be directly involved in the modification of the exocyclic amino group. 相似文献
5.
D. A. Gordenin M. V. Trofimova O. N. Shaburova Y. I. Pavlov Y. O. Chernoff Y. V. Chekuolene Y. Y. Proscyavichus K. V. Sasnauskas A. A. Janulaitis 《Molecular & general genetics : MGG》1988,213(2-3):388-393
Summary We have demonstrated that precise excision of bacterial transposon Tn5 can occur in the yeast, Saccharomyces cerevisiae. Tn5 insertions in the yeast gene LYS2 were generated by transposon mutagenesis made in Escherichia coli by means of a ::Tn5 vector. Nine insertions of Tn5 into the structural part of the yeast LYS2 gene situated in a shuttle epsiomal plasmid were selected. All the plasmids with a Tn5 insertion were used to transform yeast strains carrying a deletion of the entire LYS2 gene or a deletion of the part of LYS2 overlapping the point of insertion.All insertions inactivated the LYS2 gene and were able to revert with low (about 10-8) frequencies to lysine prototrophy. Restriction analysis of revertant plasmids revealed them to be indistinguishable from the original plasmid without Tn5 insertion. DNA sequencing of the regions containing the points of insertions, made for two revertants, proved that Tn5 excision was completely precise. 相似文献
6.
Greta Jarockyte Dominyka Dapkute Vitalijus Karabanovas Justinas V. Daugmaudis Feliksas Ivanauskas Ricardas Rotomskis 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(4):914-923
Background
Monolayer cell cultures have been considered the most suitable technique for in vivo cellular experiments. However, a lot of cellular functions and responses that are present in natural tissues are lost in two-dimensional cell cultures. In this context, nanoparticle accumulation data presented in literature are often not accurate enough to predict behavior of nanoparticles in vivo. Cellular spheroids show a higher degree of morphological and functional similarity to the tissues.Methods
Accumulation and distribution of carboxylated CdSe/ZnS quantum dots (QDs), chosen as model nanoparticles, was investigated in cellular spheroids composed of different phenotype mammalian cells. The findings were compared with the results obtained in in vivo experiments with human tumor xenografts in immunodeficient mice. The diffusive transport model was used for theoretical nanoparticles distribution estimation.Results
QDs were accumulated only in cells, which were localized in the periphery of cellular spheroids. CdSe/ZnS QDs were shown to be stable and inert; they did not have any side-effects for cellular spheroids formation. Penetration of QDs in both cellular spheroids and in vivo tumor model was limited. The mathematical model confirmed the experimental results: nanoparticles penetrated only 25 μm into cellular spheroids after 24 h of incubation.Conclusions
Penetration of negatively charged nanoparticles is limited not only in tumor tissue, but also in cellular spheroids.General Significance
The results presented in this paper show the superior applicability of cellular spheroids to cell monolayers in the studies of the antitumor effect and penetration of nanomedicines. 相似文献7.
Gaigalas M Maneliene Z Kazlauskiene R Petrusyte M Janulaitis A 《Nucleic acids research》2002,30(19):e98
A new type II restriction endonuclease designated PfoI has been partially purified from Pseudomonas fluorescens biovar 126. PfoI recognises the interrupted hexanucleotide palindromic sequence 5'-T downward arrow CCNGGA-3' and cleaves DNA to produce protruding pentanucleotide 5'-ends. 相似文献
8.
AbeI, a restriction endonuclease from Azotobacter beijerinckii, which recognizes the asymmetric heptanucleotide sequence 5'-CCTCAGC-3'(-5/-2). 下载免费PDF全文
A new restriction endonuclease Abe I has beenisolated from Azotobacter beijerinckii. This enzymerecognizes the asymmetric heptanucleotide sequence 5'-CCTCAGC-3' and cleaves within it symmetrically at positions -5/-2 in the opposing strands, producing three base protruding 5'-ends. 相似文献
9.
Investigation of restriction-modification enzymes from M. varians RFL19 with a new type of specificity toward modification of substrate. 总被引:17,自引:10,他引:7 下载免费PDF全文
V Butkus S Klimasauskas D Kersulyte D Vaitkevicius A Lebionka A Janulaitis 《Nucleic acids research》1985,13(16):5727-5746
The characterization of MvaI restriction-modification enzymes, isolated from Micrococcus varians RFL19, is reported. Both enzymes recognize the 5'CC decreases (A/T)GG nucleotide sequence. The endonuclease cleaves the sequence at the position indicated by the arrow, whereas the methylase modifies the internal cytosine, yielding N4-methylcytosine. This type of modification protects the substrate from R.MvaI cleavage. 5-Methylcytosine in the same position of the recognition sequence does not protect the substrate from R.MvaI cleavage. R.MvaI proved to be the first example of a restriction endonuclease differentiating the position of the methyl group in the heterocyclic ring of cytosine, located in the same site of the recognition sequence. M.MvaI modifies DNA dcm+ in vitro yielding N4,5-dimethylcytosine. N4-methylcytosine cannot be differentiated from cytosine using the Maxam-Gilbert DNA sequencing procedure. 相似文献
10.
Synthesis and physical characterization of DNA fragments containing N4-methylcytosine and 5-methylcytosine. 总被引:2,自引:2,他引:0
V Butkus S Klimasauskas L Petrauskiene Z Maneliene A Janulaitis L E Minchenkova A K Schyolkina 《Nucleic acids research》1987,15(20):8467-8478
The synthesis of N4-methyl-2'-deoxycytidine and its fully protected mononucleotide, suitable for the oligonucleotide synthesis by phosphotriester method is described. A set of octanucleotides - d(CGCGCGCG), d(CG5mCGCGCG), d(CG4mCGCGCG) and dodecanucleotides - d(GGACCCGGGTCC), d(GGA5mCCCGGGTCC), d(GGA4mCCCGGGTCC) has been synthesized in a solution. Physical characterization of the oligonucleotide duplexes by means of UV and CD spectrometry provides the evidence that 4mC similarly to 5mC favours the B--greater than Z transition, although both of these methylated cytosines inhibit the B--greater than A conformational change. N4-Methylcytosine in contrast to 5-methylcytosine reduces the DNA double helix thermal stability. 相似文献