Translational coupling in Escherichia coli of a heterologous Bacillus subtilis-Escherichia coli gene fusion.

The efficient expression in Escherichia coli of the Tn9-derived chloramphenicol acetyltransferase (EC 2.3.1.28) gene fused distal to the promoter and N terminus of the Bacillus subtilis aprA gene was dependent on the initiation of translation from the ribosome-binding site in the aprA gene.     

A major difference between the divergence patterns within the lines-1 families in mice and voles

L1 retroposons are represented in mice by subfamilies of interspersed sequences of varied abundance. Previous analyses have indicated that subfamilies are generated by duplicative transposition of a small number of members of the L1 family, the progeny of which then become a major component of the murine L1 population, and are not due to any active processes generating homology within preexisting groups of elements in a particular species. In mice, more than a third of the L1 elements belong to a clade that became active approximately 5 Mya and whose elements are > or = 95% identical. We have collected sequence information from 13 L1 elements isolated from two species of voles (Rodentia: Microtinae: Microtus and Arvicola) and have found that divergence within the vole L1 population is quite different from that in mice, in that there is no abundant subfamily of homologous elements. Individual L1 elements from voles are very divergent from one another and belong to a clade that began a period of elevated duplicative transposition approximately 13 Mya. Sequence analyses of portions of these divergent L1 elements (approximately 250 bp each) gave no evidence for concerted evolution having acted on the vole L1 elements since the split of the two vole lineages approximately 3.5 Mya; that is, the observed interspecific divergence (6.7%-24.7%) is not larger than the intraspecific divergence (7.9%-27.2%), and phylogenetic analyses showed no clustering into Arvicola and Microtus clades.      

Development of bis-locked nucleic acid (bisLNA) oligonucleotides for efficient invasion of supercoiled duplex DNA

In spite of the many developments in synthetic oligonucleotide (ON) chemistry and design, invasion into double-stranded DNA (DSI) under physiological salt and pH conditions remains a challenge. In this work, we provide a new ON tool based on locked nucleic acids (LNAs), designed for strand invasion into duplex DNA (DSI). We thus report on the development of a clamp type of LNA ON—bisLNA—with capacity to bind and invade into supercoiled double-stranded DNA. The bisLNA links a triplex-forming, Hoogsteen-binding, targeting arm with a strand-invading Watson–Crick binding arm. Optimization was carried out by varying the number and location of LNA nucleotides and the length of the triplex-forming versus strand-invading arms. Single-strand regions in target duplex DNA were mapped using chemical probing. By combining design and increase in LNA content, it was possible to achieve a 100-fold increase in potency with 30% DSI at 450 nM using a bisLNA to plasmid ratio of only 21:1. Although this first conceptual report does not address the utility of bisLNA for the targeting of DNA in a chromosomal context, it shows bisLNA as a promising candidate for interfering also with cellular genes.     

Soil seed bank contributes significantly to genetic variation of Hypericum sinaicum in a changing environment

The contribution of soil seed bank of a desert endemic plant species in maintaining genetic diversity has been addressed in this paper through investigating the differences in genetic diversity and structure (using AFLP markers) between plants grown from soil seed bank and standing crop plants within and among five populations of H. sinaicum growing at St. Katherine Protectorate, southern Sinai, Egypt. Standard genetic diversity measures showed that the molecular variation within and among populations was highly significantly different between standing crop and soil seed bank. While soil seed bank had lower genetic diversity than standing crop populations, pooling soil seed bank with standing crop samples resulted in higher diversity. The results revealed also that soil seed bank had lower differentiation (7 %) than among populations of the standing crop (18 %). Results of neighbor-joining, Bayesian clustering and principal coordinate analysis showed that soil seed banks had a separate gene pool different from standing crop. The study came to the conclusion that the genetic variation of the soil seed bank contributes significantly to the genetic variation of the species. This also stresses the importance of elucidating the genetic diversity and structure of the soil seed bank for any sound and long-term conservation efforts for desert species. These have been growing in small-size populations for a long time that any estimates gained only from aboveground sampling of populations may be ambiguous.     

Multifactorial diversity sustains microbial community stability

Maintenance of a high degree of biodiversity in homogeneous environments is poorly understood. A complex cheese starter culture with a long history of use was characterized as a model system to study simple microbial communities. Eight distinct genetic lineages were identified, encompassing two species: Lactococcus lactis and Leuconostoc mesenteroides. The genetic lineages were found to be collections of strains with variable plasmid content and phage sensitivities. Kill-the-winner hypothesis explaining the suppression of the fittest strains by density-dependent phage predation was operational at the strain level. This prevents the eradication of entire genetic lineages from the community during propagation regimes (back-slopping), stabilizing the genetic heterogeneity in the starter culture against environmental uncertainty.     

Immunohistochemical localization of irisin in skin,eye, and thyroid and pineal glands of the crested porcupine (Hystrix cristata)

Irisin was first identified in muscle cells. We detected irisin immunoreactivity in various organs of the crested porcupine (Hystrix cristata). In the epidermis, irisin immunoreactivity was localized mainly in stratum basale, stratum spinosum and stratum granulosum layers; immunoreactivity was not observed in the stratum corneum. In the dermis, irisin was found in the external and internal root sheath, cortex and medulla of hair follicles, and in sebaceous glands. Irisin immunoreactivity was found in the neural retina and skeletal muscle fibers associated with the eye. The pineal and thyroid glands also exhibited irisin immunoreactivity.     

Synthesis and Cytotoxicity Screening of Some Synthesized Coumarin and Aza-Coumarin Derivatives as Anticancer Agents

Russian Journal of Bioorganic Chemistry - A series of coumarin and aza-coumarin derivatives (II–IX) were synthesized and identified using IR, 1H NMR, and 13C NMR spectral data. All the...