Dynamics of chlorophyll <Emphasis Type="Italic">a</Emphasis> concentration in the South Baikal pelagic during the direct temperature stratification period

The dynamics of chlorophyll a (Chl a) concentration and water temperature (at depth layers of 0?10, 10–25, 25–50, and 50–250 m) and transparency were studied at a pelagic sampling station in South Baikal during the direct temperature stratification period (July–October) in 2009–2011. The results indicate a sufficiently stable functioning of the autotrophic chain of the Lake Baikal pelagic. The observed concentration of Chl a in the 0–50 m depth layer in July–October of 2009–2011 had varied within the range of 0.29–1.84 mg/m³ (1.03 ± 0.06 mg/m³ on average), which is close to the average multiyear values, and correlated positively with the water temperature.     

Crystal and solution structure of the C-terminal part of the <Emphasis Type="Italic">Methanocaldococcus jannaschii</Emphasis> A<Subscript>1</Subscript>A<Subscript>O</Subscript> ATP synthase subunit E revealed by X-ray diffraction and small-angle X-ray scattering

The structure of the C-terminus of subunit E (E_101–206) of Methanocaldococcus jannaschii A-ATP synthase was determined at 4.1 Å. E_101–206 consist of a N-terminal globular domain with three α-helices and four antiparallel β-strands and an α-helix at the very C-terminus. Comparison of M. jannaschii E_101–206 with the C-terminus E_81–198 subunit E from Pyrococcus horikoshii OT3 revealed that the kink in the C-terminal α-helix of E_81–198, involved in dimer formation, is absent in M. jannaschii E_101–206. Whereas a major dimeric surface interface is present between the P. horikoshii E_81–198 molecules in the asymmetric unit, no such interaction could be found in the M. jannaschii E_101–206 molecules. To verify the oligomeric behaviour, the low resolution structure of the recombinant E_85–206 from M. jannaschii was determined using small angle X-ray scattering. Rigid body modeling of two copies of one of the monomer established a fit with a tail to tail arrangement.     

Multimodal effects of nearly complete geomagnetic field deprivation on fission of the planarian <Emphasis Type="Italic">Dugesia tigrina</Emphasis>

The rate of asexual reproduction of planarians (fission) did not change upon total deprivation of the geomagnetic field (induction ±5 nT), but was 1.5–2-fold higher than in the control upon attenuation to 100–300 nT; the stimulatory effect disappeared at 400–600 nT, was almost restituted at 0.8–1.5 μT, and zeroed again at 3 μT.     

Dynamics of Chlorophyll <Emphasis Type="Italic">a</Emphasis> Content in the Ob River and its Relationship with Abiotic Factors

Seasonal and interannual dynamics of phytoplankton content (chlorophyll a), organic matter, and nutrients, as well as water temperature and water transparency, have been analyzed for the weekly observations performed in the Ob River from February to November, 2012–2015. The period of intensive phytoplankton growth (>10 mg/m³ Chl. a) lasts 70–90 days at a long spring flood in average and high-water years; in the absence of flooding during a dry year it exceeds 110 days. Seasonal phytoplankton dynamics is characterized by two summer maxima in July–August and in September (Chl. a content ~25 mg/m³); during a dry year, there is also a peak in June (up to 37.3 mg/m³). Seasonal dynamics of Chl. a in summer–autumn low water is closely related to the water temperature; in high water and autumn low water it is closely related to water transparency; in summer it is closely related to BOD5; and, in the summer–autumn period, it is closely related with nitrate content. According to the annual average (5.7–11.1 mg/m³) and maximum (19.2–35.0 mg/m³) concentrations of chlorophyll a, the trophic status of the river corresponds to mesotrophic–eutrophic water and the water quality corresponds to the second class, i.e., “clean water.”     

Epitope mapping of a monoclonal antibody directed against the α‐subunit of phosphofructokinase‐1 from Saccharomyces cerevisiae by screening phage display libraries

Phosphofructokinase‐1 from Saccharomyces cerevisiae is composed of two types of subunits, α and β. Subunit‐specific monoclonal antibodies were raised to elucidate structural and functional properties of both subunits. One monoclonal antibody, α‐F3, binds to an epitope either at the C‐terminal or at the N‐terminal part of the α‐polypeptide chain. By screening a heptapeptide library with this monoclonal antibody, a set of heptapeptides was selected, which contained the consensus sequences D–A–F and D–S–F. Two heptapeptides with these motifs were synthesized in order assess their capacity to inhibit the binding of antibody α‐F3 to native phosphofructokinase‐1. The peptide G–I–K–D–A–F–L inhibited the binding more strongly (IC₅₀ = 1.5 µM) than the peptide A–P–W–H–D–S–F (IC₅₀ = 33.3 µM). Sequence matching revealed the presence of the D–A–F motif in the polypeptide chain of phosphofructokinase‐1 at amino acid position 172–174. As a control, the nonapeptide A–P–T–S–K–D–A–F–L which corresponds to the sequence of the putative epitope was tested in the inhibition assay. In view of the high inhibitory capacity (IC₅₀ = 0.3 µM) it was concluded that this nonapeptide represents the continuous epitope of phosphofructokinase‐1 that is recognized by antibody α‐F3. Copyright © 1999 John Wiley & Sons, Ltd.     

Development of the sand dollar <Emphasis Type="Italic">Scaphechinus mirabilis</Emphasis>

Under laboratory conditions, the development of larvae of the sand dollar Scaphechinus mirabilis (Agassiz) took 28.5–29 days from fertilization to settling and the end of metamorphosis at a temperature 20°C and salinity 32.2–32.6‰ The cleavage divisions were completed in 12 hours after fertilization (AF) by the release of free swimming ciliary blastula from the egg membrane. The larvae attained pluteus I stage with one pair of arms at an age of 40 hours. In 4.5–5 days the pluteus II stage with three pairs of arms, and in 9 days the pluteus III stage with four pairs of arms were formed. On the 20–21st day AF the larvae developed a vestibule, in which the adult skeleton rudiments, spicules, plates and pedicellariae were formed on the 26–27th day AF. The size of the larvae at an age of 22.5 days was 1064.3 ± 44.7 μm. The settling of larvae was recorded on the 28–29th day of development. Most of the larvae completed their metamorphosis in 4.5–5 hours after settling.     

Mechanism of formation of the C‐terminal β‐hairpin of the B3 domain of the immunoglobulin binding protein G from Streptococcus. I. Importance of hydrophobic interactions in stabilization of β‐hairpin structure

We previously studied a 16‐amino acid‐residue fragment of the C‐terminal β‐hairpin of the B3 domain (residues 46–61), [IG(46–61)] of the immunoglobulin binding protein G from Streptoccocus, and found that hydrophobic interactions and the turn region play an important role in stabilizing the structure. Based on these results, we carried out systematic structural studies of peptides derived from the sequence of IG (46–61) by systematically shortening the peptide by one residue at a time from both the C‐ and the N‐terminus. To determine the structure and stability of two resulting 12‐ and 14‐amino acid‐residue peptides, IG(48–59) and IG(47–60), respectively, we carried out circular dichroism, NMR, and calorimetric studies of these peptides in pure water. Our results show that IG(48–59) possesses organized three‐dimensional structure stabilized by hydrophobic interactions (Tyr50–Phe57 and Trp48–Val59) at T = 283 and 305 K. At T = 313 K, the structure breaks down because of increased chain entropy, but the turn region is preserved in the same position observed for the structure of the whole protein. The breakdown of structure occurs near the melting temperature of this peptide (T_m = 310 K) measured by differential scanning calorimetry (DSC). The melting temperature of IG(47–60) determined by DSC is T_m = 330 K and its structure is similar to that of the native β‐hairpin at all (lower) temperatures examined (283–313 K). Both of these truncated sequences are conserved in all known amino acid sequences of the B domains of the immunoglobulin binding protein G from bacteria. Thus, this study contributes to an understanding of the mechanism of folding of this whole family of proteins, and provides information about the mechanism of formation and stabilization of a β‐hairpin structural element. Proteins 2009. © 2008 Wiley‐Liss, Inc.     

Stress-protective activity of the CH<Subscript>3</Subscript>CO-Lys-Lys-Arg-Arg-NH<Subscript>2</Subscript> synthetic peptide (protectin)

The CH₃CO-Lys-Lys-Arg-Arg-NH₂ peptide (the author has named it protectin) was synthesized, and its activity was studied during different stress actions. Protectin was found to normalize the content of corticosterone and adrenalin in adrenal glands and blood after its intranasal administration to rats one day before a cold or heat shock, or hypobaric hypoxia at doses of 1–10 μg/animal and after its intravenous administration just after acute hemorrhage at doses of 0.5–2 μg/animal. The intranasal administration of protectin at doses of 1–10 μg/rat one day before the heat or cold shock was also shown to prevent a change in the content of free histamine and the activity of diamine oxidase in myocardium, which was induced by the dramatic change in the activity of the enzyme after the temperature actions.     

Insights into the unfolding pathway and identification of thermally sensitive regions of phytase from <Emphasis Type="Italic">Aspergillus niger</Emphasis> by molecular dynamics simulations

Thermal stability is of great importance in the application of commercial phytases. Phytase A (PhyA) is a monomeric protein comprising twelve α-helices and ten β-sheets. Comparative molecular dynamics (MD) simulations (at 310, 350, 400, and 500 K) revealed that the thermal stability of PhyA from Aspergillus niger (A. niger) is associated with its conformational rigidity. The most thermally sensitive regions were identified as loops 8 (residues 83–106), 10 (161–174), 14 (224–230), 17 (306–331), and 24 (442–444), which are present on the surface of the protein. It was observed that solvent-exposed loops denature before or show higher flexibility than buried residues. We observed that PhyA begins to unfold at loops 8 and 14, which further extends to loop 24 at the C-terminus. The intense movement of loop 8 causes the helix H2 and beta-sheet B3 to fluctuate at high temperature. The high flexibility of the H2, H10, and H12 helices at high temperature resulted in complete denaturation. The high mobility of loop 14 easily transfers to the adjacent helices H7, H8, and H9, which fluctuate and partially unfold at high temperature (500 K). It was also observed that the salt bridges Asp110–Lys149, Asp205–Lys277, Asp335–Arg136, Asp416–Arg420, and Glu387–Arg400 are important influences on the structural stability but not the thermostability, as the lengths of these salt bridges did not increase with rising temperature. The salt bridges Glu125–Arg163, Asp299–Arg136, Asp266–Arg219, Asp339–Lys278, Asp335–Arg136, and Asp424–Arg428 are all important for thermostability, as the lengths of these bridges increased dramatically with increasing temperature. Here, for the first time, we have computationally identified the thermolabile regions of PhyA, and this information could be used to engineer novel thermostable phytases. Numerous homologous phytases of fungal as well as bacterial origin are known, and these homologs show high sequence similarity. Our findings could prove useful in attempts to increase the thermostability of homologous phytases via protein engineering.     

Mechanism of formation of the C‐terminal β‐hairpin of the B3 domain of the immunoglobulin‐binding protein G from Streptococcus. IV. Implication for the mechanism of folding of the parent protein

A 34‐residue α/β peptide [IG(28–61)], derived from the C‐terminal part of the B3 domain of the immunoglobulin binding protein G from Streptoccocus, was studied using CD and NMR spectroscopy at various temperatures and by differential scanning calorimetry. It was found that the C‐terminal part (a 16‐residue‐long fragment) of this peptide, which corresponds to the sequence of the β‐hairpin in the native structure, forms structure similar to the β‐hairpin only at T = 313 K, and the structure is stabilized by non‐native long‐range hydrophobic interactions (Val47–Val59). On the other hand, the N‐terminal part of IG(28–61), which corresponds to the middle α‐helix in the native structure, is unstructured at low temperature (283 K) and forms an α‐helix‐like structure at 305 K, and only one helical turn is observed at 313 K. At all temperatures at which NMR experiments were performed (283, 305, and 313 K), we do not observe any long‐range connectivities which would have supported packing between the C‐terminal (β‐hairpin) and the N‐terminal (α‐helix) parts of the sequence. Such interactions are absent, in contrast to the folding pathway of the B domain of protein G, proposed recently by Kmiecik and Kolinski (Biophys J 2008, 94, 726–736), based on Monte‐Carlo dynamics studies. Alternative folding mechanisms are proposed and discussed. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 469–480, 2010. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com     

Streptococcus pneumoniae PBP2x mid‐cell localization requires the C‐terminal PASTA domains and is essential for cell shape maintenance

The transpeptidase activity of the essential penicillin‐binding protein 2x (PBP2x) of Streptococcus pneumoniae is believed to be important for murein biosynthesis required for cell division. To study the molecular mechanism driving localization of PBP2x in live cells, we constructed a set of N‐terminal GFP–PBP2x fusions under the control of a zinc‐inducible promoter. The ectopic fusion protein localized at mid‐cell. Cells showed no growth defects even in the absence of the genomic pbp2x, demonstrating that GFP–PBP2x is functional. Depletion of GFP–PBP2x resulted in severe morphological alterations, confirming the essentiality of PBP2x and demonstrating that PBP2x is required for cell division and not for cell elongation. A genetically or antibiotic inactivated GFP–PBP2x still localized at septal sites. Remarkably, the same was true for a GFP–PBP2x derivative containing a deletion of the central transpeptidase domain, although only in the absence of the protease/chaperone HtrA. Thus localization is independent of the catalytic transpeptidase domain but requires the C‐terminal PASTA domains, identifying HtrA as targeting GFP–PBP2x derivatives. Finally, PBP2x was positioned at the septum similar to PBP1a and the PASTA domain containing StkP protein, confirming that PBP2x is a key element of the divisome complex.     

Acute administration of the organochalcogen 3‐methyl‐1‐phenyl‐2‐(phenylseleno)oct‐2‐en‐1‐one induces biochemical and hematological disorders in male rats

Organochalcogens are extensively produced and employed by industry and agriculture, and the risk of occupational and environmental toxicity to them has been poorly understood. Here, we investigated the acute effect of a new organochalcogen 3‐methyl‐1‐phenyl‐2‐(phenylseleno)oct‐2‐en‐1‐one on biochemical and hematological parameters in male Wistar rats. The animals were treated with a single intraperitoneal injection of the organochalcogen at doses of 125, 250 or 500 µg·kg^–1. After 60 min, the animals were sacrificed by decapitation, and the trunk blood was collected for determination of glucose, triglycerides, cholesterol, alanine aminotransferase (ALT), aspartate aminotransferase, lactate dehydrogenase, urea, creatinine, C‐reactive protein, red blood cells, hematocrit, hemoglobin and white blood cells (WBC). Our results showed a reduction in cholesterol levels in all treated groups, an increase in ALT activity at doses of 250 and 500 µg·kg^–1, a decrease of hemoglobin and an increase in WBC in animals that received 250 and 500 µg·kg^–1 of the organoselenium. In addition, we observed an increase in neutrophil counts at 125 µg·kg^–1 dose and a decrease at 500 µg·kg^–1 dose. We also verified an increase in lymphocyte counts at the dose of 500 µg·kg^–1. Thus, the present study shows that the acute treatment with this new organochalcogen causes biochemical changes and hematological disorders in male rats. Copyright © 2012 John Wiley & Sons, Ltd.     

Adaptive responses of embryos and larvae of the heart-shaped sea urchin <Emphasis Type="Italic">Echinocardium cordatum</Emphasis> to temperature and salinity changes

The combined effects of temperature (8, 12, 14, 17, 20, 22 and 25°C) and a salinity decrease from 36 to 12‰ on the development of the sea urchin Echinocardium cordatum (Pennant) were studied. Embryonic development proved to be the process most vulnerable to a salinity decrease. It was completed successfully at 8–20°C within a narrow salinity range of 36–28‰ Larvae at the most resistant stage, the blastula, survived at 12–22°C and a salinity of 36–18‰. Larvae at the most sensitive stage, pluteus I with the first pair of arms, died even in a favorable environment, a temperature of 17–20°C and a salinity of 34–28‰. That may be related to qualitative alterations during skeleton formation and to transition to phytoplankton feeding. The resistance of larvae to variations in environmental factors gradually increased in the pluteus II and III stages; however, it significantly decreased before the settling of the larvae. Larvae that were 37 days old survived at a temperature of 14–20°C within a salinity range of 36–22‰ and at 22 and 25°C, they survived at a salinity of 36–24‰; however, all the larvae became abnormal at 25°C. The larvae settled earlier on sand inhabited by adult individuals of E. cordatum than on sand from other locations, and they settled faster at 20–25°C, than at 14 and 17°C. The juveniles, if lacking an opportunity to burrow in the sand, died within 14 days after settling.     

Cold hardiness and range of the earthworm <Emphasis Type="Italic">Eisenia sibirica</Emphasis> (Oligochaeta,Lumbricidae)

A hypothesis of range formation of the earthworm Eisenia sibirica Perel et Graphodatsky 1984, which is an endemic species of the Altai–Sayan mountain system and is also found on the adjacent plains of Siberia across the valleys of the rivers, is suggested. The limited distribution of the species can be connected with the insufficient cold hardiness of the worm stage (–10 to–12°C). The plains of Western Siberia lie in an area of minimum soil temperature isotherms at a depth of 3 cm:–12 to–14°C, i.e., on average 2–4°C below the tolerable limits for this species. Foothill and mountain soils are warmer, since they obtain much more solid precipitation. Low soil temperatures of the plains apparently “lock up” this species within the Altai–Sayan system. At the same time, there are reasons to consider the northernmost locations of E. sibirica to be relict.     

BRANCHED SILKLESS mediates the transition from spikelet to floral meristem during Zea mays ear development

The molecular and genetic control of inflorescence and flower development has been studied in great detail in model dicotyledonous plants such as Arabidopsis and Antirrhinum . In contrast, little is known about these important developmental steps in monocotyledonous species. Here we report the analysis of the Zea mays mutant branched silkless1–2 (bd1–2) , allelic to bd1 , which we have used as a tool to study the transition from spikelet to floret development in maize. Floret development is blocked in the female inflorescence (the ear) of bd1–2 plants, whereas florets develop almost normally in the male inflorescence (the tassel). Detailed phenotypic analyses indicate that in bd1–2 mutants ear inflorescence formation initiates normally, however, the spikelet meristems do not proceed to form floret meristems. The ear spikelets, at anthesis, contain various numbers of spikelet-like meristems and glume-like structures. Furthermore, growth of branches from the base of the ear is often observed. Expression analyses show that the floral-specific MADS box genes Zea mays AGAMOUS1 ( ZAG1 ), ZAG2 and Zea mays MADS 2 ( ZMM2 ) are not expressed in ear florets in bd1–2 mutants, whereas their expression in tassel florets is similar to that of wild type. Taken together, these data indicate that the development from spikelet to floret meristem is differentially controlled in the ear and tassel in the monoecious grass species Zea mays , and that BRANCHED SILKLESS plays an important role in regulating the transition from spikelet meristem to floral meristem during the development of the female inflorescence of maize.     

Conformational and stacking properties of 3′–5′ and 2′–5′ linked oligoribonucleotides studied by CD

Comparative CD studies have been carried out to characterize the properties of 2′–5′ and 3′–5′ oligoriboadenylates and oligoribouridylates from dimer to decamer. The CD band of the 3′–5′ oligoribonucleotides was larger than that of the 2′–5′ oligoribonucleotides and increased with the increase in chain length, while the CD band of the 2′–5′ oligoribonucleotides increased little beyond the dimer level. The CD analysis of the chain length dependency revealed that the 3′–5′ oligoribonucleotides adopt mainly the base-base stacking interaction, while the base-sugar interaction is predominant in the 2′–5′ oligoribonucleotides. The CD intensity of 3′–5′ oligoribonucleotides decreased to a larger extent at elevated temperatures or in the presence of ethanol compared to that of the 2′–5′ counterparts. Mg²⁺ or Mn²⁺ ion enhanced the magnitude of the CD of 3′–5′ octariboadenylate, while a small decrease in the CD was observed by the presence of Mg²⁺ or Mn²⁺ ion to the 2′–5′ octariboadenylate. The 3′–5′ oligoribonucleotide is likely conformationally flexible and can form helical ordered structure with strong base-base stacking depending on changes in the environment such as temperature, the presence of Mg²⁺ ion, or hydrophobicity of the solution. © 1996 John Wiley & Sons, Inc.     

The effects of KB-R7943, an inhibitor of reverse Na<Superscript>+</Superscript>/Ca<Superscript>2+</Superscript> exchange,on the force of contraction of papillary muscles in the heart of the ground squirrel <Emphasis Type="Italic">Spermophilus undulatus</Emphasis>

We investigated the effect of KB-R7943, an inhibitor of the reverse mode of Na⁺/Ca²⁺ exchanger, on the force of isometric contractions, the contractile force–frequency relationship and post-rest potentiation (a qualitative parameter of Ca²⁺ levels in sarcoplasmic reticulum) in the right ventricle papillary muscles isolated from ground squirrel hearts during summer (June, n = 4) and autumn (October, n = 4) activities. In the presence of 1.8 mM Ca2+at 36°C, 1–1.5 hours-long treatment of the summer papillary muscles with KB-R7943 produced no significant effects on the contractile indices at the majority of stimulation frequencies. In the autumn papillary muscles KB-R7943 induced a 40–50% decrease in the force of contraction (negative inotropic effect) at low stimulation frequencies (0.1–0.3 Hz) without any significant effect at higher stimulation frequencies (0.4–3.0 Hz). Furthermore, in this group, KB-R7943 suppressed the post-rest potentiation of contractility by 50 ± 21% at pause durations exceeding 120 s. These observations indicate that KB-R7943 can affect Ca²⁺ levels in sarcoplasmic reticulum and that Na⁺/Ca2⁺ exchange may contribute to the physiological remodeling of intracellular Ca²⁺ homeostasis in myocardium of hibernating animals prior their transition to a hypometabolic torpid state.     

IR and Raman spectroscopy in the study of carotenoids of <Emphasis Type="Italic">Cladophora rivularis</Emphasis> algae

Using Raman and infrared spectroscopy it has been found that during the normal life of algae (pH changes from 8.0 to 9.0) the content of carotenoids increases and the molecules change their conformation: the contribution of–C=C–bonds of the polyene chain of a carotenoid molecule (Raman spectroscopy) is reduced and the contribution of methyl groups (～2940 cm^–1) and aromatic C–H-plane deformation vibrations (band at 1050 cm^–1) of carotenoid molecules (infrared spectroscopy) decreases as well. It is the opinion of the authors that a change in the extracellular pH within the normal range has no influence on the content of chlorophyll a and b, but tends to increase the content and alter the conformation or structure of carotenoid molecules.     

Theoretical investigation of the mechanism for the reductive dehalogenation of methyl halides mediated by the Co<Superscript>I</Superscript>-based compounds cobalamin and cobaloxime

Theoretical calculations focusing on the cleavage of the C–X bond in methyl halides (CH₃X; X?=?Cl, Br, I) as mediated by Co^I-based systems have been carried out using the hybrid functional ωB97-XD together with the basis set 6–311++G(2d,2p). A total of seven Co^I-based compounds were evaluated: cob[I]alamin (Co^ICbl) in its base-on form and cobaloxime (Co^ICbx) with either no ligand or different ligands (either pyridine (PYR), tributylphosphine (TBP), dimethyl sulfide (DMS), cyclohexylisocyanide (CI), or 5,6-dimethylbenzimidazole (DMB)) at the lower axial position. For the large Co^ICbl system, an ONIOM scheme was employed, where the high layer was described at the DFT level and the low layer was computed using the semi-empirical method PM6. A full DFT model was employed for the Co^ICbx cases. An S_N2-like mechanism was evaluated in all cases. The intrinsic reaction coordinate profiles suggested early transition states with activation energies of ≈ 12 kcal/mol, ≈ 10 kcal/mol, and ≈ 5 kcal/mol for C–Cl, C–Br, and C–I cleavage, respectively, which is consistent with the leaving group abilities of these halides. The evolutions of the atomic charges in and the bond orders of Co–C and C–X were computed, and the results confirmed the existence of early transition states (δB_av≈ 40%), where the polarization C^δ+–X^δ? (%E_v?≈?43%) is the determining factor in the reaction process. Finally, a comparison of all the determined parameters showed that the reaction in the DMB–Co^ICbx system resembles the process that occurs in the larger Co^ICbl, suggesting that the former system could be a reliable model for the study of reductive dehalogenation mediated by vitamin B₁₂, which is key to the anaerobic microbiological treatment of halocarbon contaminants.     

First data on the biology of <Emphasis Type="Italic">Hadropareia middendorffii</Emphasis> (Perciformes,Zoarcidae) in the Tauysk Bay,the Sea of Okhotsk

Data of long-term studies (1997–2013) on biology of Hadropareia middendorffii from different areas of Tauysk Bay, the Sea of Okhotsk are generalized. This species is widespread over the entire northern coast of the Sea of Okhotsk, and it prefers sandy-pebbly grounds. Maximum sizes and age comprise 267 mm, 73 g, and 7+; in catches, individuals with a length of 9.1–12.0 cm, weight 0.1–10.0 g, at an age of 1+ to 3+ dominate. In general size–age characteristics of females and males as a whole are rather similar, and sex ratio is nearly equal. Hadropareia middendorffii spawns from the second half of June to the first 10-day period of August; its fecundity varies within 67–219 eggs.