Time filter

Source Type

Vladivostok, Russia

Khotimchenko Y.S.,Institute of Marine Biology
Russian Journal of Marine Biology

This review is devoted to the pharmacological properties of carrageenans, alginates, and pectins. The summarized results of the studies dedicated to the antitumor activity of the natural polysaccharides and their modified derivates are given. Brief information regarding the structure and physicochemical properties of these polysaccharides and detailed descriptions of the molecular mechanisms of antitumor and antimetastatic effects are given. © 2010 Pleiades Publishing, Ltd. Source

Pudovkin A.I.,Institute of Marine Biology | Zhdanova O.L.,Institute of Automation and Control Processes | Hedgecock D.,University of Southern California
Conservation Genetics

The effective number of breeders (Nb) for a cohort of progeny can be estimated from an excess of heterozygotes that arises in progeny produced by finite numbers of parents. In principle, Nb is a simple function of the standardized deviation (D) of the proportion of heterozygous progeny from its expectation under random mating. We explored the sampling properties of this D-estimator of Nb through computer simulation. The accuracy of the D-estimator is remarkably robust to variation in numbers of alleles and loci and the presence of rare alleles, though precision can be low if, relative to a given Nb, the sample of progeny or the cumulative number of independent alleles (nci) sampled is too small. For Nb up to 30 parents, acceptable accuracy is achieved with sample sizes of 200 or more progeny and 80 or more independent alleles; for Nb of 50-100, a sample of 500-1,000 progeny and 450-900 independent alleles are required for similar accuracy and precision. Though the estimator is most applicable for the situation of random union of gametes (as may occur in some marine invertebrates or fish, for example), it works for other mating systems (monogamous or polygamous pairings, polygyny), when the effective number of breeders is small (Nb ≤ 20). Simulations reveal small overestimation biases with smaller sample sizes, rare alleles, or highly polymorphic loci (≥10 alleles). Despite this bias, multiallelic loci are preferable to many loci with few alleles, which have larger sampling errors. © 2009 Springer Science+Business Media B.V. Source

Khotimchenko Y.S.,Institute of Marine Biology
Russian Journal of Marine Biology

This review deals with the pharmacology of nonstarch polysaccharides, namely fucoidans and chitosans, isolated from marine organisms. The work summarizes information from the international literature on the antitumor activities of native polysaccharides and their derivatives. The structures and physicochemical properties of these polysaccharides are described and the molecular mechanisms of their antitumor and antimetastatic effects are discussed. © 2010 Pleiades Publishing, Ltd. Source

Borovikov Y.S.,Russian Academy of Sciences | Shelud'ko N.S.,Institute of Marine Biology | Avrova S.V.,Russian Academy of Sciences
Archives of Biochemistry and Biophysics

The effect of twitchin, a thick filament protein of molluscan muscles, on actin-myosin interaction at several mimicked sequential steps of the ATPase cycle was investigated using fluorescent probes specifically bound to Cys707 of myosin subfragment-1 and Cys374 of actin incorporated into ghost muscle fibers. The multi-step changes in mobility and spatial arrangement of myosin SH1 helix and actin subdomain-1 during the ATPase cycle have been revealed. For the first time, the inhibition of movement of myosin SH1 helix and actin subdomain-1 during the ATPase cycle and the decrease in the myosin head and actin affinity in the presence of unphosphorylated twitchin have been demonstrated. Phosphorylation of twitchin by the catalytic subunit of protein kinase A reversed this effect. These data imply a novel property of twitchin consisting in its ability to regulate in a phosphorylation-dependent manner the actin-myosin interaction during the ATPase cycle by the inhibition of transformation of the weak-binding actomyosin states into the strong-binding ones. © 2010 Elsevier Inc. All rights reserved. Source

Bensman S.J.,Louisiana State University | Smolinsky L.J.,Louisiana State University | Pudovkin A.I.,Institute of Marine Biology
Journal of the American Society for Information Science and Technology

This paper analyzes the applicability of the article mean citation rate measures in the Science Citation Index Journal Citation Reports (SCI JCR) to the five JCR mathematical subject categories.These measures are the traditional 2-year impact factor as well as the recently added 5-year impact factor and 5-year article influence score. Utilizing the 2008 SCI JCR, the paper compares the probability distributions of the measures in the mathematical categories to the probability distribution of a scientific model of impact factor distribution. The scientific model distribution is highly skewed, conforming to the negative binomial type, with much of the variance due to the important role of review articles in science. In contrast, the three article mean citation rate measures' distributions in the mathematical categories conformed to either the binomial or Poisson, indicating a high degree of randomness. Seeking reasons for this, the paper analyzes the bibliometric structure of Mathematics, finding it a disjointed discipline of isolated subf ields with a weak central core of journals, reduced review function, and long cited half-life placing most citations beyond the measures' time limits.These combine to reduce the measures' variance to one commensurate with random error. However, the measures were found capable of identifying important journals. Using data from surveys of the Louisiana State University (LSU) faculty, the paper finds a higher level of consensus among mathematicians and others on which are the important mathematics journals than the measures indicate, positing that much of the apparent randomness may be due to the measures' inapplicability to mathematical disciplines. Moreover, tests of the stability of impact factor ranks across a 5-year time span suggested that the proper model for Mathematics is the negative binomial. © 2010 ASIS&T. Source

Discover hidden collaborations