Influence of Manganese on Growth of a Sheathless Strain of Leptothrix discophora

Mn²⁺ exerted various effects on the growth of Leptothrix discophora strain SS-1 in batch cultures depending on the concentration added to the medium. Concentrations of 0.55 to 5.5 μM Mn²⁺, comparable to those in the environment from which strain SS-1 was isolated, decreased cell yield and prolonged stationary-phase survival, but did not affect growth rate. Elevated concentrations of 55 to 910 μM Mn²⁺ also decreased cell yield and prolonged survival, but growth rate was decreased as well. The addition of 1,820 μM Mn²⁺ caused a decline in cell numbers followed by an exponential rise after 80 h of incubation, indicating the development of a population of cells resistant to Mn²⁺ toxicity. When 360 μM Mn²⁺ or less was added to growth flasks, Mn²⁺ was oxidized to manganese oxide (MnO_x, where x is ~2), which appeared as brown particles in the medium. Quantification of Mn oxidation during growth of cultures to which 55 μM Mn²⁺ was added showed that nearly all of the Mn²⁺ was oxidized by the beginning of the stationary phase of growth (15 to 25 h). This result suggested that the decrease in cell yield observed at low and moderate concentrations of Mn²⁺ was related to the formation of MnO_x, which may have bound cationic nutrients essential to the growth of SS-1. The addition of excess Fe³⁺ to cultures containing 55 μM Mn²⁺ increased cell yield to levels near those found in cultures with no added Mn²⁺, indicating that iron deprivation by MnO_x was at least partly responsible for the decreased cell yield.     

Role of calcium in the initiation of fast axonal transport of protein: Effects of divalent cations

Fast axonal transport of [³H]protein has been examined in bullfrog primary afferent neurons incubated in media supplemented with divalent cations that can act as agonists or antagonists of calcium ions. Incubation in calcium-free medium (CFM) had no effect on the rate of transport, but reduced the amount of transported [³H]protein by 40–60% relative to transport in the contralateral preparation maintained in normal medium. Preparations incubated in CFM supplemented with 1.8 mM SrCl₂ (equimolar to the CaCl₂ concentration in normal medium) carried out transport at control levels. Incubation conditions in which primary afferent somata were exposed to the Sr²⁺-medium while nerve trunks were maintained in CFM also supported normal transport. By contrast, selective exposure of nerve trunks to Sr²⁺-medium, and somata to CFM resulted in a reduced level of transport similar to that observed when the whole preparation was incubated in CFM. The depression of transport resulting from incubation in CFM was shown to be reversible when preparations were transferred from CFM to either Sr²⁺-supplemented CFM or to normal medium. By contrast to the effects of Sr²⁺, Ba²⁺ (up to 18 mM) did not substitute for Ca²⁺ in the transport process. When normal medium was supplemented with calciumantagonist cations, the amount of transport was depressed (Co²⁺ > Mn²⁺ >> Mg²⁺), with no concomitant effect on the rate of transport. Results of studies with Co²⁺, as well as those with Sr²⁺, suggest that a major locus of action of these cations is within the neuronal soma at a step subsequent to protein synthesis, and prior to the onset of protein translocation via the transport system. Thus, it is inferred that these divalent cations affect a calcium-dependent step that occurs during the initiation phase of fast axonal transport.     

Serological comparisons of seed proteins of some representatives of the genusAllium

Results obtained by comparison of similarity of seed protein spectra of 15 species of the genusAllium (in 22 samples) by means of immunochemical methods more or less correspond to the contemporary division of this genus. Species belonging to the sectionCepa (according to Vvedenskiy) andPhyllodolon have very similar spectra, which suggests that they either should be allocated to one sectionCepa or to two subsections (Cepa andPhyllodolon). Species belonging to the subgenusRhizirideum considerably differ in seed proteins. The investigated species of the subgenusMelanocrommyum show the most distinct spectrum of all the other analyzed representatives, less marked differences were found in the case of the representatives of the subgenusAllium.     

Chemistry of the “molecular trap” of protease-catalyzed splicing reaction of complementary segments of α-subunit of hemoglobin A

The complementary fragments of human Hb α, α_1–30, and α_31–141 are spliced together by V8 protease in the presence of 30%n-propanol to generate the full-length molecule (Hb α-semisynthetic reaction). Unlike the other protease-catalyzed protein/peptide splicing reactions of fragment complementing systems, the enzymic condensation of nonassociating segments of Hb α is facilitated by the organic cosolvent induced α-helical conformation of product acting as the “molecular trap” of the splicing reaction. The segments α_24–30 and α_31–40 are the shortest complementary segments that can be spliced by V8 protease. In the present study, the chemistry of the contiguous segment (product) α_24–40 has been manipulated by engineering the amino acid replacements to the positions α²⁷ and α³¹ to delineate the structural basis of the molecular trap. The location of Glu²⁷ and Arg³¹ residues in the contiguous segment α_24–40 (as well as in other larger segments) is ideal to generate (i, i+4) side-chain carboxylate-guanidino interaction in its α-helical conformation. The amino acid residue replacement studies have confirmed that the side chains at α²⁷ and α³¹ facilitate the semisynthetic reaction. The relative influence of the substitute at these sites on the splicing reaction depends on the chemical nature of the side chain and the location. The γ-carboxylate guanidino side-chain interaction appears to contribute up to a maximum of 85% of the thermodynamic stability of the molecular trap. The studies also demonstrate that the thermodynamic stability of the molecular trap is determined by two interdependent conformational aspects of the peptide. One is an amino acid-sequence-specific event that facilitates the induction of an α-helical conformation to the contiguous segment in the presence of organic cosolvent that imparts some amount of protease resistance to Glu³⁰-Arg³¹ peptide bond. The second structural aspect is a site-specific event, ani, i+4 side-chain interaction in the α-helical conformation of the peptide which imparts an additional thermodynamic stability to the molecular trap. The results suggest that conformationally driven “molecular traps” of protease-mediated ligation reactions of peptides could be designed into products to facilitate the modular assembly of peptides/proteins.     

Studies on the effects of subzero temperatures on the viability of spores of Aspergillus flavus. I. The effect of rate of warming

1. The survival of spores of Aspergillus flavus suspended in distilled water and cooled rapidly to –70 to –75°C. was found to depend primarily on the rate of subsequent warming of the frozen suspension. Only 7 per cent of the spores germinated following slow warming at 0.9°C. per minute, whereas about 75 per cent germinated following rapid warming at 700°C. per minute. 2. Viability was dependent on the rate at which the suspensions warmed from –70 to 0°C. (subzero warming), but was not dependent on the rate of thawing of the frozen water in which the spores were suspended. 3. The logarithm of the percentage of germination appeared to be a linear function of the logarithm of the rate of subzero warming when spores were warmed at rates ranging from 0.12 to 1000°C. per minute. 4. The lethal effects of slow warming from –70 to 0°C. were more pronounced between about –20 and 0°C. than between –70 and –20°C. In the former range of temperatures, the percentage of germination decreased sharply as slow warming progressed towards 0°C. 5. Slow warming from –70 to 0°C. was more harmful to the spores than was a 1 or 2 hour exposure to constant temperatures between –70 and 0°C. 6. Slow warming was found to be more harmful than rapid warming when spores were suspended in horse serum, 0.16 molal sodium chloride, or 0.29 molal sucrose as well as in distilled water.     

Potential of active excretion of ammonia in three different haline species of crabs

Isolated perfused gills of stenohaline crabs Cancer pagurus adapted to seawater, brackish water-adapted euryhaline shore crabs Carcinus maenas and freshwater-adapted extremely euryhaline Chinese crabs Eriocheir sinensis were tested for their capacity to excrete ammonia. Gills were perfused with haemolymph-like salines and bathed with salines equal in adaptation osmolality. Applying 100 μmol · l⁻¹ NH₄Cl in the perfusion saline and concentrations of NH₄Cl in the bath that were stepwise increased from 0 to 4000 μmol · l⁻¹ allowed us to measure transbranchial fluxes of ammonia along an outwardly as well as various inwardly directed gradients. The gills of all three crab species were capable – to different extents – of active excretion of ammonia against an inwardly directed gradient. Of the three crab species, the gills of Cancer pagurus revealed the highest capacity for active excretion of ammonia, being able to excrete it from the haemolymph (100 μmol · l⁻¹ NH⁺ ₄) through the gill epithelium against ambient concentrations of up to 800 μmol · l⁻¹, i.e. against an eightfold gradient. Carcinus maenas and E. sinensis were able to actively excrete ammonia against approximately fourfold gradients. Within the three crab species, the gills of E. sinensis exhibited the greatest capacity to resist influx at very high external concentrations of up to 4000 μmol · l⁻¹. We consider the observed capacities for excretion of ammonia against the gradient as ecologically meaningful. These benthic crustaceans protect themselves by burying themselves in the sediment, where, in contrast to the water column, concentrations of ammonia have previously been reported that greatly increase haemolymph levels. Electrophysiological results indicate that the permeabilities of the gill epithelia are a clue to understanding the species-specific differences in active excretion of ammonia. During the invasion of brackish water and freshwater, the permeabilities of the body surfaces greatly decreased. The gills of marine Cancer pagurus exibited the greatest permeability (ca. 250 mS cm⁻²), thus representing practically no influx barrier for ions including NH⁺ ₄. We therefore assume that C. pagurus had to develop the strongest mechanism of active excretion of ammonia to counteract influx. On the other hand, freshwater-adapted E. sinensis exhibited the lowest ion permeability (ca. 4 mS cm⁻²) which may reduce passive NH⁺ ₄ influxes at high ambient levels. Accepted: 14 October 1998     

Absence of sodA Increases the Levels of Oxidation of Key Metabolic Determinants of Borrelia burgdorferi

Borrelia burgdorferi, the causative agent of Lyme disease, alters its gene expression in response to environmental signals unique to its tick vector or vertebrate hosts. B. burgdorferi carries one superoxide dismutase gene (sodA) capable of controlling intracellular superoxide levels. Previously, sodA was shown to be essential for infection of B. burgdorferi in the C3H/HeN model of Lyme disease. We employed two-dimensional electrophoresis (2-DE) and immunoblot analysis with antibodies specific to carbonylated proteins to identify targets that were differentially oxidized in the soluble fractions of the sodA mutant compared to its isogenic parental control strain following treatment with an endogenous superoxide generator, methyl viologen (MV, paraquat). HPLC-ESI-MS/MS analysis of oxidized proteins revealed that several proteins of the glycolytic pathway (BB0057, BB0020, BB0348) exhibited increased carbonylation in the sodA mutant treated with MV. Levels of ATP and NAD/NADH were reduced in the sodA mutant compared with the parental strain following treatment with MV and could be attributed to increased levels of oxidation of proteins of the glycolytic pathway. In addition, a chaperone, HtpG (BB0560), and outer surface protein A (OspA, BBA15) were also observed to be oxidized in the sodA mutant. Immunoblot analysis revealed reduced levels of Outer surface protein C (OspC), Decorin binding protein A (DbpA), fibronectin binding protein (BBK32), RpoS and BosR in the sodA mutant compared to the control strains. Viable sodA mutant spirochetes could not be recovered from both gp91/phox ^−⁄− and iNOS deficient mice while borrelial DNA was detected in multiple tissues samples from infected mice at significantly lower levels compared to the parental strain. Taken together, these observations indicate that the increased oxidation of select borrelial determinants and reduced levels of critical pathogenesis-associated lipoproteins contribute to the in vivo deficit of the sodA mutant in the mouse model of Lyme disease. This study, utilizing the sodA mutant, has provided insights into adaptive capabilities critical for survival of B. burgdorferi in its hosts.     

Characterization of adaptability components of Brazilian isolates of Macrophomina pseudophaseolina

Macrophomina pseudophaseolina is a new Macrophomina species reported on different crop and weed species in Brazil, India and Senegal, but to date there are no studies about its adaptability components. In this work, a collection of 62 M. pseudophaseolina isolates obtained from roots of the weed species Trianthema portulacastrum and Boerhavia diffusa collected in Northeastern Brazil, was used to: (a) study the effect of temperature and salinity on mycelial growth, (b) to determine their sensitivity to the fungicide carbendazim and (c) to assess their aggressiveness on melon and watermelon seedlings. Results showed variability among M. pseudophaseolina isolates. The optimum temperature for mycelial growth ranged between 26.4 and 38.1ºC. NaCl reduced the in vitro growth of all isolates, which were also highly sensitive to the fungicide carbendazim, exhibiting EC₅₀ values ranging from 0.013 to 0.089 mg/L a.i. Disease severity values on melon and watermelon seedlings showed that M. pseudophaseolina isolates were more aggressive in melon than in watermelon. Information about adaptability components of M. pseudophaseolina obtained in this study could be incorporated on breeding programs for melon and watermelon crops.     

Contraction of protoplasm. III. Cinematographic analysis of the contraction of some heterotrichs

The contraction of Stentor and Blepharisma, in response to mechanical and electrical stimulation and of Spirostomum in response to mechanical stimulation is described. All three species respond to electrical stimulation by contraction of the cytoplasm, beginning at the anodal end regardless of orientation of the animal. The differences in contractile ability and shapes during contraction are discussed in relation to body form and microanatomy. Stentor and Spirostomum also respond to mechanical stimulation. Dropping a weight on the slide causes contraction of the whole body of Spirostomum, but not of Stentor. Stimulation of the oral region of Stentor by means of a vibrating needle causes a contraction of the entire body, but this sensitivity is limited to the oral region. Blepharisma does not respond to mechanical stimulation. Spirostomum and Stentor undergo rapid spontaneous contractions, but Blepharisma does not contract spontaneously.     

Influence of Volume of Nutrient Agar Medium on Development of Colonies of Marine Bacteria

Zusammenfassung Bei der Bestimmung der Anzahl Bakterien in frisch genommenen Seewasserproben mit dem Plattengußverfahren reduziert eine Agarmenge von über 10 ml die Anzahl sich entwickelnder Kolonien. Die erhaltenen Zahlen sind im allgemeinen am höchsten und die Ergebnisse am besten reproduzierbar, wenn genau 10 ml des Nähragars benutzt wird im Gegensatz zu unbestimmten Mengen zwischen 5 und 30 ml. Obgleich auch andere Faktoren eine Rolle spielen, wird der ungünstige Einfluß von Agarmengen, die merklich größer als 10 ml sind, in erster Linie den langsameren Abkühlungsraten während des üblichen Plattengußverfahrens zugeschrieben. Wenn Nähragar von 42° C bei Raumtemperatur (22–24° C) in Pyrex-Petrischalen gegossen wurde, kühlten 10 ml in ca. 1 min. auf 30° C ab, während 5 bis 24 min. gebraucht wurden, um Agarmengen von 20 bis 50 ml von 42° C auf 30° C abzukühlen. Viele marine Bakterien werden geschädigt, wenn sie Temperaturen ausgesetzt werden, die über 30° C liegen, wobei das Ausmaß der Schädigung von der Einwirkungszeit abhängt. Deswegen ist es überaus wichtig, daß der Agar vor dem Gießen auf 42° C gekühlt wird. Die Abkühlungsrate des Agarmediums in den Platten wird von der Beschaffenheit und der Temperatur der Tischoberfläche, auf der die Platten stchen, beeinflußt.

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Plating the heterogeneous bacteria occuring naturally in samples of raw sea water with volumes of molten nutrient agar exceeding 10 ml reduces the number of colonies which develop. Plate counts on replicate samples of sea water are generally highest and results are more nearly reproducible when 10 ml of nutrient agar is used rather than volumes ranging randomly from 5 to 30 ml. Although other factors are involved, the adverse effects of volumes of nutrient agar appreciable larger than 10 ml are attributed primarily to the slower cooling rates during conventional plating procedures. When nutrient agar medium at 42° C was poured into pyrex Petri dishes at room temperature (22–24° C), 10 ml of the medium cooled to 30° C in about one minute, whereas from about 5 to 24 minutes were required for 20 to 50 ml of the medium to cool from 42° C down to 30 ° C. Many marine bacteria are injured by being subjected to temperatures higher than 30° C, the extent of the injury being a function of time. Therefore, it is of paramount importance that agar be cooled to 42° C prior to pouring. The rate at which agar medium cools in plates is influenced by the composition and temperature of the table top on which the plates rest.

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Contribution from the Scripps Institution of Oceanography, University of California, La Jolla, California.     

Comparison of various ways of extraction of nucleic acids and of preparation of yeast extract from saccharomyces cerevisiae and candida utilis

Six different variations of the extraction procedure applied to yeast cells of Saccharomyces cerevisiae and Candida utilis to optimize the production of yeast extract and isolation of nucleic acids were compared. The autolysis of C. utilis at 50 to 52°C without adding chemical agents was found to be the best for the production of yeast extract. The most suitable procedures used for the extraction of nucleic acids were those which were carried out from C. utilis at pH 7.5 (92°C) and the other with 0.4 M NH₄OH (40°C). Both these modifications yielded the highest amounts of polymer nucleic acids. Applying all procedures compared to S. cerevisiae an increased content of sterols (including Δ^5.7-sterols, predominantly ergosterol) was detected.     

Analysis of morphogenetic mutants of hydra

Summary A mutant ofHydra attenuata is analysed, theaberrant, which is distinct from the wild type in having a smaller head with fewer tentacles and only half the number of head-specific cells. The rate of head and foot regeneration and the doubling time are slower inaberrants than in normal hydra.The lower head-forming potential is paralleled by a reduced concentration of head-specific morphogens: compared to the wild type, in theaberrant the concentration of head activator is reduced to 70% in the head and to 50% in the body, the concentration of head inhibitor is reduced to 50% in the head and to 80% in the body. Theaberrant is more sensitive (3 times) to added head activator and less sensitive (>5 times) to added head inhibitor than the wild type.The slower rate of foot regeneration is paralleled by a lower content of foot-specific morphogens: compared to the wild type, in theaberrant the foot activator is reduced to 40% and the foot inhibitor to 70%.     

Mode of action of antitumour antibiotics-III: Modulation of permeability of nuclear membrane in the presence of the antibiotics

The binding characteristics of the antibiotics to nuclei and their effect on the permeability of nuclear membrane with respect to histones and ribonucleic acids have been investigated. The binding constant for chromomycin A₃ was found to be 1.4 × 10⁴M^?1 and number of binding sites was equal to 3.48 ± 1.08 × 10¹² molecules/nuclei. The antibiotic chromomycin A₃ enhanced the uptake of lysine-rich histone, actinomycin D decreased the uptake and ethidium bromide had no effect. Chromomycin A₃ also enhanced the release of acid insoluble fraction containing RNA from the nuclei, actinomycin D and ethidium bromide inhibited the release of acid insoluble fraction containing RNA. The relevance of this finding to the role of nuclear envelope in understanding the mechanism of action of the antibiotic has been discussed.     

Pathogenicity of Four Species of Meloidogyne on Three Varieties of Olive Trees

''Ascolano'' and ''Sevillano'' olive trees, Olea europaea L., were highly susceptible to Meloidogyne javanica (Trueb) Chitwood, and growth of their tops was decreased greatly in tests in a glasshouse. Roots of ''Manzanillo'' olive trees were galled moderately by M. javanica, and their tops weighed 6% less than those of noninoculated trees. ''Manzanillo'' olive is considered highly tolerant to M. javanica. ''Ascolano'' and ''Manzanillo'' olive trees were highly susceptible to M. incognita (Kofoid &White) Chitwood. Their roots were galled moderately to severely, and growth of their tops were decreased between 13% and 44%. ''Ascolano'' and ''Manzanillo'' olive trees were considered to be highly resistant to M. arenaria (Neal) Chitwood and M. hapla Chitwood since no galls or mature females were found on their roots three and one-half months after inoculation.     

Non-Productive Binding of Substrates as One of Aspects of Substrate Specificity of Cholinesterases of Different Origin

Taking into account the phenomenon of non-productive binding of substrate, kinetic parameters of hydrolysis of acetylcholine (ACh) and its 13 derivatives with different structures of ammonium group by cholinesterase (ChE) of human erythrocytes, ChE of horse blood serum, and ChE of optic ganglia of the Pacific squid Todarodes pacificus are determined. A dependence is revealed of values of parameters of their enzymatic hydrolysis and parameters of the non-productive binding on the substrate structure and ChE nature. Effects of salts, LiCl, NaCl, KCl, MgCl₂, CaCl₂ and BaCl₂, on various kinetic parameters, including parameters of the non-productive binding of substrate, of enzymatic hydrolysis of iodides of ACh and N-acetoxyethylene-N-ethylpiperidinium under action of horse blood serum ChE are studied. Addition of the salts to the reaction mixture produced different effects on values of the catalytic center activity (a _c) and the Michaelis constant (K _M), depending on the cation nature and the substrate structure. At the same time, values of the a _c/K _M ratio that characterize to a degree the substrate affinity to the enzyme are equal to each other for two substrates differing in structure, regardless of the presence and nature of the studied cations. Parameters of the non-productive binding of N-acetoxyethylene-N-ethylpiperidinium iodide also depended on the salt nature; however, in that case, a question arises as to the correctness of the comparative analysis, when at determinations of the parameters the non-productive binding of ACh is ignored.     

非计划再次手术关键环节管理与效果分析

目的 探索有效降低非计划再次手术发生率的管理方法。方法 对2012年1月—2016年12月住院并进行手术的患者进行主动监测,加强管理,发现非计划再次手术病例,统计发生率及引发原因。结果 225 944例手术共发生非计划再次手术914例,平均发生率为0.40%且五年呈显著下降趋势。引发原因以手术部位感染、切口裂开、切口疝或愈合不良,术后出血,出现漏或瘘为主,共占73.9%。结论 完善主动监测与报告系统、加强院科两级管理、注重原因分析与改进可有效降低非计划再次手术的发生率。     

A review of length–weight relationships of fishes from freshwaters of Turkey

This paper presents 145 length–weight relationships gathered from the literature pertaining to 30 Turkish freshwater fish species belonging to six families. The value of the slope b ranged from 2.04 for Carassius carassius to 3.46 for Scardinus erythroptalmus. The mean value of b was 2.91 (SD = 0.305), which did not differ significantly from 3.0 (t‐test, P > 0.05). The median value of b was 2.95; 50% of the b values ranged from 2.68 to 3.14. The plot of log a vs b was used to detect outliers.     

Mechanism of action of cholera toxin: Effect of receptor density and multivalent binding on activation of adenylate cyclase

Summary Cl^– influx into cells ofChara corallina is shown to be stimulated by a factor of 2 to 4 by starvation of Cl^–. The time constant for the induction of this effect is about 4.0 ksec and that for its decay when Cl^– is reprovided, 1.7 ksec. Intracellular perfusion of tonoplast-free cells with solutions of varying Cl^– concentration shows that Cl^– influx can be controlled directly by the concentration of Cl^– at the inside of the plasma membrane. Both the time course for the initial stages of induction of the starvation-stimulated flux and its absolute magnitude can be accounted for by assuming cytoplasmic Cl^– concentration to be the only intracellular condition to change during Cl^– starvation. The existence of a feedback loop between cytoplasmic Cl^– and Cl^– influx provides an alternative explanation to observations previously used in support of a Cl^–/OH^– exchange hypothesis (F.A. Smith, 1972,New Phytol. 71:595).     

Effect of lactoferrin on oxidative features of ceruloplasmin

In our previous report we first described a complex between lactoferrin (Lf) and ceruloplasmin (Cp) with K _d ~ 1.8 μM. The presence of this complex in colostrum that never contains more than 0.3 μM Cp questions the reliability of K _d value. We carefully studied Lf binding to Cp and investigated the enzymatic activity of the latter in the presence of Lf, which allowed obtaining a new value for K _d of Cp–Lf complex. Lf interacting with Cp changes its oxidizing activity with various substrates, such as Fe²⁺, o-dianisidine (o-DA), p-phenylenediamine (p-PD) and dihydroxyphenylalanine (DOPA). The presence of at least two binding sites for Lf in Cp molecule is deduced from comparison of substrates’ oxidation kinetics with and without Lf. When Lf binds to the first site affinity of Cp to Fe²⁺ and to o-DA increases, but it decreases towards DOPA and remains unchanged towards p-PD. Oxidation rate of Fe²⁺ grows, while that of o-DA, p-PD and DOPA goes down. Subsequent Lf binding to the second center has no effect on iron oxidation, hampers DOPA and o-DA oxidation, and reduces affinity towards p-PD. Scatchard plot for Lf sorbing to Cp-Sepharose allowed estimating K _d for Lf binding to high-affinity (~13.4 nM) and low-affinity (~211 nM) sites. The observed effect of Lf on ferroxidase activity of Cp is likely to have physiological implications.     

Bacterial Abundance and the Activity of Microbiological Processes in the Bay of Tugur of the Sea of Okhotsk

This paper presents the results of investigation of the total abundance and the biomass of bacterioplankton, the abundance of heterotrophic bacteria, and the activity of microbiological processes involved in the carbon cycle in the water of the Bay of Tugur of the Sea of Okhotsk. In different regions of the bay, the total abundance of bacterioplankton was found to vary from 0.51 × 10⁶ to 2.54 × 10⁶ cells/ml; the bacterioplankton biomass, from 8.5 to 46.5 g C/l; the abundance of heterotrophic bacteria, from 0.06 × 10³ to 2.12 × 10³ cells/ml; the bacterial assimilation of CO₂, glucose, acetate, and protein hydrolysate, from 0.8 to 6.3, from 0.11 to 1.88, from 0.07 to 0.56, and from 0.01 to 0.22 mg C/(m³ day), respectively; the degradation of organic matter ranged from 28 to 221 mg C/(m³ day); and the intensity of methane oxidation, from 0.0005 to 0.17 l CH₄/l. The spatial pattern and the functional characteristics of bacterioplankton in the Bay of Tugur were found to be dependent on the tidal dynamics.