Further comment on drag and reconfiguration of macrophytes

1. The paper by Sand‐Jensen (2003 , Freshwater Biology, 48 , 271), and the subsequent comment and reply ( Sukhodolov, 2005 , Freshwater Biology, 50 , 194; Sand‐Jensen, 2005 , Freshwater Biology, 50 , 196), are discussed. I present partial theory describing how the macrophyte bending angle changes with increased flow velocity, demonstrating a nonlinear relation. 2. While Sand‐Jensen (2005) is correct that plant wetted area is the only characteristic area that can be measured easily, some other measure of the exposure area of the plant stand to the flow may be preferable. The relationship in Sand‐Jensen (2003) between the dimensionless drag coefficient and flow velocity depends on the definition of characteristic area. Hence, the analysis involving the drag parameter in Sand‐Jensen (2003) should be interpreted with care.     

Further comment on the distinction between humans and animals

The problem of mind is considered in the aspect of natural scientific and philosophical problem of distinction between human and animal. The widespread confusion of the terms "rudiments", "elements" of specifically human properties in animals and "biological prerequisites" of these properties are critically analysed. The idea is formulated according to which only in the process of anthropogenesis the rudiments of new social property--mind, conscience--could appear in the developing human beings.     

Further comment on the significance of data on fish parasites for related disciplines

The significance of data on fish parasites was earlier considered by V. A. Dogel', S. S. Shul'man, S. M. Konovalov, and other Soviet parasitologists. These data are inadequately used by related disciplines. The possibility to use parasitological data for studying fish feeding pattern, peculiarities of their bathymetric distribution, migration routes, taxonomy, phylogenetic origin, and revealing the origin of marine basins and their ichthyofauna has been demonstrated.     

Ecological and biological maintenance of sapronoses exemplified by melioidosis

The growth and death of Pseudomonas pseudomallei, the causative agent of melioidosis, in the soil and the antigenic properties of this microorganism in the soil, in culture media, and in the body of animals have been studied. As revealed in this study, P. pseudomallei can grow in nonsterile soil substrates without the loss of virulence and changes in its antigenic structure. In the body of animals this microorganism rapidly adapts its virulence to host species by the transformation of its antigenic structure. The pathogenicity factors of P. pseudomallei are mainly thermolabile antigens, probably exoenzymes. This microorganism has been shown to have close ecological relations with abiotic environmental objects. The author suggests that the type of relationship between saprophytic microorganisms acting as causative agents of diseases and warm-blooded hosts should be characterized as pseudoparasitic.     

The genomic fingerprinting of the causative agents of sapronoses

The genome polymorphism of the causative agents of sapronoses (Vibrio cholerae, Legionella and Leptospira) has been studied. The use of the method of genome fingerprinting [correction of dactyloscopy] has been shown to permit the differentiation of closely related strains of such causative agents. The epidemically significant strains of the causative agents of sapronoses, isolated in different geographical regions, have been found to be genotypically related, i.e., they are probably of clonal origin. Avirulent and nontoxigenic strains are genotypically heterogeneous and differ both from one another and from epidemically significant strains. Using V. cholerae as an example, the hypothesis of the appearance of potentially dangerous variants at the epidemic period in the absence of their release at the period between epidemics is considered.     

Further comment on the coccidian nature of cryptosporidia (Sporozoa: Apicomplexa)

The coccidian nature of the genus Cryptosporidium was undoubtedly accepted by Tyzzer who was the first to describe this sporozoan parasite in 1907. Electron microscopic studies made in 70-90s demonstrated the intracellular, although extracytoplasmic localization of Cryptosporidium spp. The pattern of Cryptosporidium life cycle fits well that of other intestinal homogeneous coccidian genera of the suborder Eimeriina: macro- and microgamonts develop independently, a microgamont gives rise to numerous male gametes, oocysts serving for parasite's spreading in the environment. Along with these characters, Cryptosporidium spp. demonstrate some secondary peculiarities (an endogenous phase of development in microvilli of epithelial surfaces, two morphofunctional types of oocysts, the smallest number of sporozoites per oocyst, a multi-membraneous "feeder" organelle etc.), which may be due presumably to their early acquisition of specialization in the course of evolution. The recent studies based on molecular sequence data (18S rRNA) applied to 8 eimeriid and isosporid coccidian genera (Morrison, Ellis, 1997), suggested that the subclass Coccidia (class, according to Morrison and Ellis) be considered monophylic if Cryptosporidium were excluded, and this genus was regarded as the sister group to the rest of the Apicomplexa, or as the sister to the suborder (class) Hematozoa within the Apicomplexa. Either of these placements of Cryptosporidium definitely conflicts with both the generally accepted taxonomic scheme by Levine (1982) and the phenotypically based phylogeny of the phylum Apicomplexa (Barta e. a., 1990). The author's opinion is that the differences between the examined eimeriid and isosporid coccidia, on the one hand, and Cryptosporidium, on the other hand, provided by molecular sequence data, may testify primarily to the well known morphofunctional dissimilarities between the compared organisms, rather than cast doubt on the coccidian nature of Cryptosporidium. Again, these data can hardly prove that Cryptosporidium does not belong to the coccidia. Thus, the modern molecular sequence data, despite their obvious scientific value, would make sense for phylogeny estimation only, if they are critically analysed and considered in combination with results of the relevant basic research.     

Hydrobionts as reservoir hosts for infectious agents of bacterial sapronoses

Data on parasitism of the infectious agents of sapronoses in hydrobionts (protozoans, crustaceans, worms, mollusks, echinoderms, and fishes) are considered from the population-ecological viewpoint. The symbiotic relationships between populations of pathogenic bacteria and protozoans are of the host-parasite type. An ultrastructural analysis demonstrates that phagocytosis is incomplete both in planktonic forms and in biofilms formed by bacteria and protozoa. This provides for long-term survival of infectious agents in the environment. The migration of Yersinia pseudotuberculosis along trophic chains from the lowest to the highest level has been simulated experimentally. The long-term survival of pathogenic bacteria in aquatic animals and the ability of bacteria to migrate along trophic chains, reaching soil animals and humans, provide evidence that comprehensive studies on the routes of circulation of pathogens in natural ecosystems are highly relevant from the ecological and epidemiological viewpoints.     

Microbiological monitoring of causative agents of sapronoses in the water of the Bogatinskoe water reservoir

The results of the microbiological monitoring of potential causative agents of sapronoses in the water of the Bogatinskoye reservoir revealed that in the summer period of 1998 the mass accumulation of virulent Aeromonas sobria (up to 25% of the total number of heterotrophic bacteria) took place. The autumn period was characterized by a decrease in the number of A. sobria and the detection of bacteria of the genus Vibrio (up to 22%) with V. mimicus and V. metschnikovii identified among them in the water ecosystems of the southern regions of the Maritime Territory.     

A comment on phylogenetic correction

Statistical methods are now commonly used to take into account the expected lack of independence of observations across different species (due to their phylogenetic relatedness) when computing correlations or regressions among traits. The methods are often interpreted as removing that part of the regression or correlation that is an artifact due to phylogeny and there is an expectation that the corrected regression or correlation coefficients will usually be closer to zero. It is shown here that this is not an accurate way to interpret these methods. The effect of taking phylogeny into account is to reduce the variance of the estimated regression or correlation coefficients. Their means are not because since estimates of regression coefficients are unbiased whether or not the correct phylogeny is taken into account. Estimates of correlations are only slightly biased (and in the opposite direction that many expect).