(An algorithm for determining values of parameters of the Gompertz growth function)]

In the literature some attempts were made to analyse and to construct models for biological growth processes and to describe the quantitative aspects of a growth characteristic's changes in time using the Gompertz' function y=aexp(-exp(b--ct)). In this paper differential equations are derived having the Gompertz' function as solution. The goodness of fit after adjusting a chosen analytical expression to the courses of measured values is able to give hints at the reliability of that expression as a true model. This possibility of verification was hardly practiced in past because of lacking in proper numerical procedures for performing the nonlinear regression. An ALGOL program for iterative adjusting the parameters of the GOMPERTZ' function (with or without a constant term) to measured values is given in an appendix of the present paper. Starting values for the nonlinear parameters b and c will be evaluated by Internal Least Squares using one of the derived differential equations. For this algorithm an ALGOL program is given in the appendix too. The growth of human embryo serves as an example to demonstrate the numerical procedures and related programs for evaluating the starting values of the parameters and for their iterative improvement until reaching a minimum for the remainding variance between calculated and measured courses.     

The ecology of communities of related animal species (research approaches and methods exemplified by terrestrial vertebrates)]

The review is dedicated to some old and modern problems in studying of the assemblages of phylogenetically related species among terrestrial vertebrates. The classical approach by Robert Mac-Arthur, discussed elsewhere summarized briefly. Although an explanative potential of competition theory seems exhausted there is no new paradigm that can simply explain species diversity in natural communities. From the beginning of 90's community ecology became very complex and controversial discipline. At the same time it is still a pioneering science. We have not enough comparative data on geo2 graphically distinct communities studied under the unified methods of data collection and analysis. Some recent results of intercontinental comparisons signify to the high degree of individualism in structure of geographically isolated communities. This makes doubtful any extrapolation from one region to another. Examination and explanation of processes is still the most contradictory field in community ecology. Confusion of causes and effects is continuing to be serious methodological problem. Much of attention was paid recently to the macroecological approach. A desire for reconsideration of some "old rules" of biodiversity is explained by advances in paleozoology, biogeography and systematic, as well as by some unsatisfactory explanations within the framework of competition theory.     

The Early Cambrian colonization of pelagic niches exemplified by Isoxys (Arthropoda)

The anatomy of the bivalved arthropod Isoxys (Early and Middle Cambrian) is reconstructed, based on new evidence from soft parts and exoskeletal design and on a critical review of previous work. Isoxys had a long segmented body flanked with a pair of short antennules, followed by a series of 14 biramous appendages provided with long paddle-like exopods concealed under a widely open bivalved carapace folded dorsally and bearing long cardinal spines. The close resemblance between Isoxys and Recent pelagic crustaceans (halocyprid ostracods, larval stages of malacostracans) indicates that Isoxys was probably an active epipelagic swimmer (evidence from soft parts, carapace design and distributional pattern). Some species (e.g. I. auritus and I. paradoxus from the Maotianshan Shale biota; Early Cambrian) may have lived in the vicinity of the bottom either permanently or temporarily, whereas others may have had ecological preferences for more open-marine settings. The spinosity of Isoxys had a possible role in predatorial deterrence rather than in buoyancy control or in retarding sinking within the water column. The presence of Isoxys in the Maotianshan Shale of S. China indicates that arthropods had already colonized midwater niches by the Early Cambrian. The midwater communities of the Maotianshan Shale comprised numerous other invertebrates, such as abundant medusiform eldonids, vetulicolids, chordates and possibly early vertebrates. This contradicts the opinion that pelagic communities remained poorly developed until late Cambrian/Ordovician times and that the occupation of the midwater niches largely post-dates the initial diversification of the benthic faunas.     

The role of fish parasites in fresh-water ecosystems exemplified by a parasite of the smelt (Osmerus eperlanus)

The European smelt Osmerus eperlanus had been accidentally introduced into the ecosystem of the Syamozero Lake (Karelia). The population of this species has achieved a high density and caused serious changes in the structure and trophic relationships of fish community of the Syamozero ecosystem. The microsporidia Glugea hertwigi Weisenberg, 1921 has become a new and super-dominant parasite of the european smelt in this ecosystem. The invasion of microsporidia has caused a mass death of fishes, that has led to changes in population structure of the smelt and lowered a fish catch. The present study suggests to show a role of parasites in the ichthyocenosis structure regulation in freshwater ecosystem.     

Microbiological monitoring for the causative agents of nosocomial infections (exemplified by resuscitation and intensive therapy units)]

More than 900 isolates from at least 1500 patients were tested within 1996-1998. Gram-negative organisms were the main pathogens isolated from patients with different forms of nosocomial complications such as late pneumonia, associated with artificial ventilation of the lungs, and various secondary wound or urinary tract infections. The prevalence of Pseudomonas aeruginosa was stated. Antibioticograms showed that the most active drugs were imipenem (more than 90 per cent of the susceptible isolates) and ticarcillin/clavulanate (48-58 per cent of the susceptible isolates). The activity of ticarcillin/clavulanate (Timentin) was practically the same as that of imipenem against 21 strains of P.aeruginosa isolated from the blood and cerebrospinal fluid of 21 patients with sepsis and 3 patients with secondary purulent meningitis.     

Neuronal organization of the inspiratory center (Baumgarten's nucleus)]

The inspiratory center or the Baumgarten's nucleus consists of large multipolar neurons and small reticular cells of the associative field. This nucleus is divided into a number of less populations with more close anatomical connections. In its turn each such population consists of groups of nerve cells characterized by the presence of large central (one or two) neurons surrounded by small reticular cells. Basing on available microelectrode studies and the personal investigations, the author puts forward a supposition that the group under study (the respiron) as the main part of the population represents the least structural unit on which the integrative activity of the inspiratory center is based.     

The principles of QTL analysis (a minimal mathematics approach)

The combination of combination marker and trait data to explore the individual genes concerned with quantitative traits, QTL analysis, has become an important tool to allow biologists to dissect the genetics of complex characters. However, the mathematical and statistical techniques involved have deterred many from understanding what the methods achieved and appreciating their strengths and weaknesses.This paper is designed to give a non-mathematical explanation of the principles underlying these analyses, to discuss their potential and to provide an introduction to the techniques used in the subsequent papers in this series of articles based on the SEB symposium.Key words: Gene mapping, QTL analysis, quantitative genetics.      

Species-forming involution of pathogenic bacteria as a biological pattern (exemplified by bacteria of the genus Moraxella)

The author advances a hypothesis stating that a species disappearing as a result of new conditions evolving in a colonized animal or human body, unfavorable for the existence of this species, does not become extinct, but reverts into newly developing species due to the loss of its properties and acquiring new properties corresponding to new conditions. Thus the genus is preserved through the loss of species characteristics by individual organisms. The advanced hypothesis is substantiated by the analysis of the relevant processes observed in cases of infectious keratoconjunctivitis in humans and cattle, caused by bacteria of the genus Moraxella. The data indicating the possibility of such reversion in the genera Neisseria and Bordetella are presented.     

An analysis of the viability of clonal plants based on a morphometric approach (exemplified by Calamagrostis langsdorffii)

Clonal plants viability has been studied on the basis of morphostructure variability of clone modules. The research has been carried out on the Calamagrostis langsdorffii (Poaceae) in the flood-lands of the Amur River Basin (Khabarovsk Territory). Plants vitality has been evaluated by 26 morphometric parameters, characterizing their growth, productivity and reproduction. Clone ramets differed from each other by considerable variability and plasticity. Significant changes of all morphometric parameters according to humidity and alluvion gradients were very specific. Reproductive parameters were the most stable ones. Parameters of growth and dimension were characterised by increased variability. Wide reaction of morphometric parameters of C. langsdorffii to the changes in ecological conditions can be considered as an adaptation to the existence in dynamical environment of the flood-land.     

The sterologic method of determining the surface area of the mammalian neocortex]

A method for calculation of the square surface area of the cerebral cortex is proposed which represents a combination of the method of averaged reconstruction after a continuous series of histological sections and the stereological method of determination of the length of any curve disposed on the surface. A comparative analysis of the proposed method with curvometrical and stereological (after Hennig's formula) method used earlier for this purpose is made taking as an example the calculation of the neocortex square surface area of some mammals. The results of calculation of the surface by the proposed method were found to coincide with curvometrical data within the range of 5% while the data obtained by stereological method of determination of the absolute square surface area differ from curvometrical data by more than 22%. The proposed method is very convenient and allows considerable acceleration in obtaining results.     

Functional relevance of G-protein-coupled-receptor-associated proteins,exemplified by receptor-activity-modifying proteins (RAMPs)

The calcitonin (CT) receptor (CTR) and the CTR-like receptor (CRLR) are close relatives within the type II family of G-protein-coupled receptors, demonstrating sequence identity of 50%. Unlike the interaction between CT and CTR, receptors for the related hormones and neuropeptides amylin, CT-gene-related peptide (CGRP) and adrenomedullin (AM) require one of three accessory receptor-activity-modifying proteins (RAMPs) for ligand recognition. An amylin/CGRP receptor is revealed when CTR is co-expressed with RAMP1. When complexed with RAMP3, CTR interacts with amylin alone. CRLR, initially classed as an orphan receptor, is a CGRP receptor when co-expressed with RAMP1. The same receptor is specific for AM in the presence of RAMP2. Together with human RAMP3, CRLR defines an AM receptor, and with mouse RAMP3 it is a low-affinity CGRP/AM receptor. CTR-RAMP1, antagonized preferentially by salmon CT-(8-32) and not by CGRP-(8-37), and CRLR-RAMP1, antagonized by CGRP-(8-37), are two CGRP receptor isotypes. Thus amylin and CGRP interact specifically with heterodimeric complexes between CTR and RAMP1 or RAMP3, and CGRP and AM interact with complexes between CRLR and RAMP1, RAMP2 or RAMP3.