Effect of Actinomycin D on Salinity Acclimation of Paramecium calkinsi (Ciliophora, Peniculia)

Salinity acclimation of the euryhaline ciliate Paramecium calkinsi evaluated by swimming velocity was accomplished within four to five days. In two series of the main experiment, acclimation continued for two and three days when actinomycin D (an inhibitor of DNA-dependent RNA polymerase) was added after various periods of the ciliate incubation at a different salinity (0, 3, 6, and 24 h). Experimental results indicate that the inhibitory effect of actinomycin D on salinity acclimation of P. calkinsi is manifested only within the first day of the ciliate incubation in an altered environment; by the end of this period, their swimming velocity becomes similar to the control one (acclimation in the absence of the inhibitor). Thus, the expression of genes associated with salinity acclimation in the paramecium is largely completed within the first day, while acclimation continues for at least 4–5 days. We propose that the acclimation-competent species possess a correspondingly more complex genetic program.     

Monitoring of the Bewick’s Swan in the tundra zone in Yakutia

In 1982—1995 and 2007 the Bewick’s swan was monitored. The air record routes were 48 000 km long. An increase in population, widening of the range in the north and west directions are recorded. The data on dynamics of population, territorial location, social structure, and breeding parameters are given. The ecological problems related to the increase in the swan population are discussed.     

Substrate specificity and biochemical properties of M3.BstF5I DNA methyltransferase from the BstF5I restriction-modification system

Optimal conditions for DNA methylation by the M3.BstF5I enzyme from Bacillus stearothermophilus and kinetic parameters of λ phage DNA modification and that of a number of oligonucleotide substrates are established. Comparison of M1.BstF5I and M3.BstF5I kinetic parameters revealed that with similar temperature optima and affinity for DNA, M3.BstF5I has nearly fourfold lower turnover number (0.24 min⁻¹) and modifies the hemimethylated recognition site with lower efficiency under optimal conditions than the unmethylated one. In contrast to another three methylases of the BstF5I restriction-modification system, the M3.BstF5I enzyme is able to optionally modify the noncanonical 5′-GGATC-3′ DNA sequence with a rate more than one order of magnitude lower than the methylation rate of the canonical 5′-GGATG-3′ recognition site.     

The Role of Phosphate Anions in Autoinduced and Photoinduced Oxidation of NADH

Biophysics - The effects of mono- and disubstituted phosphates on the photolysis reaction of reduced nicotinamide adenine dinucleotide (NADH) in a frozen (77 K) aqueous solution were studied by...     

The ecology of the habitats, nesting, and migration of the eastern population of the siberian crane (Grus leucogeranus Pallas, 1773)

The structure of the distribution range and population of the Siberian crane in its regular breeding area in the northeastern Yakutian tundra are described, as well as the migration terms, intensity, routes, and stopover sites. The territorial pairs (71.7–97.1% of the summer population), which in 2006 were represented by the birds at ages of 8 to 21 years (mainly 20 years, accounting for 45.4%), constantly stayed on an area of 7.3–16.5 km² independently of their participation in breeding. The breeding success in this population varies from 4.3–8.7 to 65.0–83.3% and depends on the climatic conditions at the beginning of egg laying; these climatic conditions change rather unpredictably from year to year, as well as being seasonally unstable. This explains that fact that some generations in this population are particularly vulnerable to natural elimination factors because of their low numbers. Bird migration in Yakutia follows a narrow tunnel with the highest migratory intensity in the Middle Aldan Valley. In the fall, 30 to 50% of the entire population is visually recorded there.     

Circumpolar variation in morphological characteristics of Greater White-fronted Geese Anser albifrons

Capsule Greater White-fronted Geese show significant variation in body size from sampling locations throughout their circumpolar breeding range.

Aims To determine the degree of geographical variation in body size of Greater White-fronted Geese and identify factors contributing to any apparent patterns in variation.

Methods Structural measures of >3000 geese from 16 breeding areas throughout the Holarctic breeding range of the species were compared statistically.

Results Palearctic forms varied clinally, and increased in size from the smallest forms on the Kanin and Taimyr peninsulas in western Eurasia to the largest forms breeding in the Anadyr Lowlands of eastern Chukotka. Clinal variation was less apparent in the Nearctic, as both the smallest form in the Nearctic and the largest form overall (the Tule Goose) were from different breeding areas in Alaska. The Tule Goose was 25% larger than the smallest form. Birds from Greenland (A. a. flavirostris) were the second largest, although only slightly larger than geese from several North American populations. Body size was not correlated with breeding latitude but was positively correlated with temperature on the breeding grounds, breeding habitat, and migration distance. Body mass of Greater White-fronted Geese from all populations remained relatively constant during the period of wing moult. Morphological distinctness of eastern and western Palearctic forms concurs with earlier findings of complete range disjunction.

Conclusions Patterns of morphological variation in Greater White-fronted Geese across the Holarctic can be generally attributed to adaptation to variable breeding environments, migration requirements, and phylo-geographical histories.     

Microorganisms of Lake Baikal and Lake Nyasa as Indicators of Anthropogenic Influence: Prospects for Use in Biotechnology

Restriction endonucleases (RENs) were detected in 650 microbial strains isolated from water columns and bottom sediments of deep rift lakes, Baikal (Russia) and Nyasa (Southeastern Africa). They enzymes included unique (Fan I, Aca I, and Sse 91) and very rare (Bsi I, and Cci N I) species not typical of aquatic ecosystems. Water columns, deep cores, and bottom sediments of pure areas of the lakes contained no microorganisms with new RENs. Thus, the inshore areas of Lake Baikal, having been exposed to anthropogenic influences, may contain mutant bacterial strains expressing RENs that have not been described previously.