V. N. Lopatin

The Effect of Mineral Particulate Matter on the Productive Characteristics of Bacterioplankton and the Degradation of Labile Organic Material

The effect of mineral particulate matter on the population of bacterioplankton, its aggregation, and productive characteristics was studied in model experiments with different concentrations of particulate kaolin and the same concentration of organic substance (sodium humate). It was found that the presence of mineral particulate matter stimulated the aggregation of bacterioplankton, improved bacterial production, and extended the productive period of bacterioplankton. The integral specific production of aggregated bacterioplankton was higher than that of free-swimming bacterioplankton. The energy metabolic coefficient K2 of bacterioplankton in the presence of mineral particulate matter was higher than in its absence.

The Role of Specific Cell Surface in Phytoplankton Productivity

It should be noted that the optical properties of suspensions are significantly determined by specific surface area. If several suspensions have equal specific surface areas and equal volumes (i.e., equal S / V values), their optical absorptions are also equal to each other. Because, under otherwise identical conditions, a fine-dispersion suspension has a larger surface area than a large-sized suspension of equal volume, the former absorbs light more effectively than the latter. Obviously, this is of particular importance in the case of photosynthesizing cells [10]. The goal of this work was to find an empirical correlation of the phytoplankton community’s production characteristics with the algal biomass boundary surface area. To attain this goal, the species composition, cell count ( N ), biomass ( B ), and cell size of each species of phytoplankton were determined in the Yenisei River and Lake Khanka. Conventional algological methods were used. The primary production ( P ) of the algal community was measured using the light-and-dark bottle oxygen method. The results of the study showed that both in Lake Khanka and in the Yenisei River, an increase in the S / V ratio was accompanied by a statistically significant increase in the specific production of photosynthesis (gross production per biomass unit) or assimilation index ( K as , day —1 ) calculated per carbon. The respective

Functional activity of blood cells in fish exposed to radiochemical industrial sewage.

144 There is always a possibility that radionuclides will leak from industrial enterprises entailing radiation/nuclear hazards, migrate to neighboring biocenoses, and accumulate in organisms at different levels of food pyramids [1, 2]. As a result, fish that constantly live in zones with increased concentrations of radionuclides relative to background may exhibit the effect of internal low-dose irradiation [3]. Recent radiobiological studies demonstrated that external low-dose irradiation caused in mammalian cells numerous structural rearrangements, which persisted long after the irradiation and altered the cell functional activity, especially in their proand antioxidant systems [4]. These systems control physiologically predetermined generation of reactive oxygen species (ROSs) by antigen-activated immunocompetent cells maintaining the nonspecific immune resistance. All other conditions being the same, significant changes in the kinetics of ROS generation by blood cells after the incorporation of radionuclides into fish bodies may serve as indicators of early negative changes that have not yet been expressed at the cellular or tissue level. Chemiluminescent analysis seems to be a promising tool for detecting these changes.

Chemiluminescence Analysis of the Functional Activity of Phagocytizing Cells of Fish Blood

Reactive oxygen species (ROSs), such as superoxide anion, hydroperoxide, hydroxyl radical, hypochlorite, etc., are always generated during the activation and function of fish blood cells in the course of phagocytosis and represent a component of bactericidal, antiviral, and antiparasitic immunity [1, 2]. However, hypoor hyperproduction of the ROSs related to an inherited or acquired deficiency of oxidative and antioxidative cell systems may cause immune deficiency, inflammation, and pathologies. In view of this, information on the oxygenous-metabolism rate in phagocytizing cells is important for estimating the state of nonspecific resistance, potential resources of the immunogenesis system, and the extent of the detrimental effect of the environment [3]. In particular, this information may be obtained by recording the kinetics of the ROS generation by antigen-activated blood cells during all stages of phagocytosis using luminol-dependent chemiluminescence [4 − 6]. The purpose of this work was to perform comparative analysis of the characteristics of oxygenous metabolism of in vitro antigen-activated blood cells of different fish species inhabiting different biotopes of a natural water body (using the Krasnoyarsk Reservoir as an example). We used 1080 fish of different ages and sexes, belonging to five species: the roach ( Rutilus rutilus L., 153 fish), bream ( Abramis brama L., 331 fish), dace ( Leuciscus leuciscus baicalensis , 29 fish), perch ( Perca fluviatilis , 481 fish), and pike ( Esox lucius , 86 fish), which were captured after spawning in the summer of the years 2000 and 2001, in the middle region of the Krasnoyarsk Reservoir (including bays). The functional activity of fish blood cells stimulated by antigens in vitro was estimated by the kinetics of ROS generation recorded by the micromethod of luminol-amplified chemiluminescence using the CL-3604 chemiluminometer–lgraph.exe hardware–software complex [7]. The parameters analyzed were the amplitude of the peak of the chemiluminescence curve ( I max , pulses per second (pps)), time required to reach the maximum ( T max , min), and the total chemiluminescence recorded for 120 min ( S , pulses).

Functional characteristics of bacterioplankton with reference to its aggregation in water bodies of different types

The functional characteristics of bacterioplankton have been studied with reference to its aggregation in water bodies of different types. Several methods were used for calculation of the total numbers of bacteria and proportion of aggregated cells. Analysis of the experimental data has shown a relationship between the functional characteristics of bacterioplankton, such as bacterial production, destruction of organic matter, and energy coefficient, and the proportion of aggregated bacteria. It has been shown that as this proportion increases, the production per cell and energy coefficients also increase.

Effect of Preliminary Filtration on the Functional Characteristics of Bacterioplankton from Lake Khanka

The dependence of the functional characteristics of bacterioplankton from the loess of Lake Khanka on the pore size of filtering materials was investigated. Soluble organic matter (SOM), bacteria, and bacterial consumers adsorbed on particles suspended in the lake water were found to filter differently depending on the pore size of the filtering material. Filters with pore size 4.5 μm (filters II) retained up to 20% of SOM and 20–30% of bacterial cells. Filters III with pore size 2.87 μm retained almost 50% of SOM and about 40% of bacteria. The double layer of gauze no. 72 (referred to as filter I) with pores size 40 μm was unable to completely retain bacterial consumers. In the case of filtrates I and II, the generation time of bacterioplankton decreased with its increasing average daily concentration. In the case of filtrate III, the generation time of bacterioplankton was minimum and did not depend on its concentration. Oxygen consumption rates per one bacterial cell and per unit biomass in filtrates increased with decreasing pore size of the filters through which they had passed. The bacterial biomass and oxygen consumption rate increased exponentially in filtrates III and logarithmically in filtrates I.

Investigation of Bacterioplankton in the Loess-containing Lake Khanka

Some characteristics of bacterioplankton—generation time, daily (P) and specific (P/B) bacterioplankton production, and bacterial metabolic coefficientK2—in the loess-containing Lake Khanka were determined using five modifications of the bacterial-count procedure with the fluorescent dyes fluorescamin and erythrosin. Experiments showed that the organomineral complex (OMC) in this lake is broken down by chemoorganoheterotrophic bacteria. The increase in the loess content of the lake water intensified bacterial growth and the cycles of potassium, silicon, and other biogenic elements. The addition of starch to a loess suspension activated the breakdown of OMC due to the adsorption of starch on the OMC/water interface and stimulation of the metabolism of attached bacteria.