State of the pacific oyster Crassostrea gigas (Thunberg, 1793) population in the Losos Bight (Sakhalin Island) in 2013–2020

The state of the aggregation of Pacific oyster Crassostrea gigas (Thunberg, 1793) in the Losos Bight (Aniva Bay) in 2013–2020 was assessed. For now, this aggregation has been in depression as a result of intense fishing. The abundance of the aggregation of commercial individuals (shell height >120 mm) was poor two recent years. The total stock estimated is 31.5 t; the commercial stock – 4.7 t.

Dynamics of stock for yesso scallop Mizuhopecten yessoensis (Jay, 1856) in the northwestern Tatar Strait from the beginning of its fishery to nowadays

Settlements of yesso scallop Mizuhopecten yessoensis in the northwestern Tatar Strait (within the waters of Khabarovsk Region) are considered on the data of scuba (< 20 m depth) and dredge (> 20 m depth) surveys conducted in 2001–2018. To 2018, only two settlements remain in this area from 9–12 ones in 2010–2014; both remained settlements have no commercial value. Trend to decreasing of the settlements density is shown: the mean density was 3.0 ind./m2 in 2001, 0.20 ind./m2 in 2010, and 0.0005 ind./m2 in 2018. Commercially valuable scallops with the shell height > 120 mm prevailed in the settlements (86–100 %), whereas juveniles were rare or absent (1.6 %, on average) in all years of surveys. CPUE decreased from 200 kg/diver/hour in 2001–2003 to 10 kg/diver/hour in 2018. These changes are obviously reasoned by overexploitation of the population using dredging and scuba gathering. Total commercial stock of yesso scallop dropped to the minimal value in 2018: 200 t, that was in 4.5 times lower than the established limit. Thus, 5 years ban is established for M. yessoensis landing in the area.

FISHERY CHARACTERISTICS OF PIKE ESOX LUCIUS (L.) OF TOPO-PYAOZERO RESERVOIR (WHITE SEA CATCHMENT AREA)

The article presents the results of the work carried out within the framework of forecast topics and economic contractual topics aimed to assess the stock and production of pike in the Topo-Pyaozero (Kumskoe) Reservoir. There have been studied its main biological and structural-population indicators. Calculations of indicators of pike’s abundance and biomass at the present stage, necessary for the rational regulation of the fishery have been carried out. It was found that the fishing possibilities of the presented pike populations correspond to the production possibilities of its sexually mature part and the value obtained as a result of the biomass increase. Pike should be taken into the commercial operation from the age of 4+ years and older. The performed calculations of the stock size based on the materials of 2009–2020 recommend the volume of the pike total allowable catch at the present stage not less than 36 tons, or 21% of the value of the commercial stock (at the maximum rate of 23.4%). From the results of observations it follows that the abundance and stocks of pike in the Topo-Pyaozero Reservoir make it possible to provide large volumes of catch at the present time, and the total catch can be increased to the calculated values the volume of the allowable catch, provided that a rational fishery is maintained in water bodies. The intensity of fishing and an increase in pike catches in the reservoir should be considered as mandatory measures in terms of biological reclamation in reservoirs

Morphological And Molecular Identification of Double Flowered Stock (Matthiola Incana R. Br) Cultivars With High Fertility

Garden stock (Matthiola incana R. Br.) is a commercially important horticultural crop owing to its ornamental effect. There are different stock cultivars varied in color and shape, especially flowered phenotype is an essential index evaluating its commercial value, because double flowered cultivars have more brilliant flowers compared to single flowered one. The present work aimed: (1) to make superior cultivars with different colors, high fertility, being capable of early selecting only double flowered seedlings by leaf color and to investigate morphological characteristics and (2) to select RAPD and ISSR primers for the cultivar certification and identification to culture and produce good commercial stock cultivars. Here we obtained new double flowered stock cultivars with different colors including pink, pale pink and white, through outcrossing between “white” cultivar (high fertile but unable to select double flower phenotype) and “pink” cultivar (vice. versa). Among newly obtained stock cultivars, single and double flower seedlings are distinguishable from each other by leaf color, having about 70% of fertility. Moreover RAPD and ISSR markers selected in this study can be applied to identify different stock cultivars in seed production, culture and to establish cultivar certification system.

Resources and structure of horsemussel Modiolus kurilensis settlements in Peter the Great Bay (the Sea of Japan)

Modiolus kurilensis F. R. Bernard, 1983 (Mollusca, Bivalvia) can be found in Peter the Great Bay (the Sea of Japan) both on soft and hard substrates, often together with the mussel Crenomytilus grayanus (Dunker, 1853); it is a promising commercial species. This mollusc is a by-catch when catching C. grayanus. The aim of the work was to assess M. kurilensis resources and settlement structure in Peter the Great Bay. The research was carried out in 2007–2018 by scuba-diving methods of hydrobiological research at the depths of down to 20 m. In total, the data were analyzed for 2,409 stations; M. kurilensis was found at 308 stations. Sampled molluscs were measured and weighed. The material was processed statistically and cartographically; the mean biomass and distribution density of M. kurilensis settlements were calculated. In total, 870 horsemussels were analyzed for studying the settlement structure. The following indicators were estimated: index of settling (ratio of the abundance of juvenile molluscs with a shell length of 1–30 mm (spat, yearlings) to the abundance of adults with a shell length of > 50 mm); index of maturation (ratio of the abundance of pre-reproductive molluscs with a shell length of 35–50 mm to the abundance of adults with a shell length of > 50 mm); index of replenishment of the commercial stock (ratio of the abundance of molluscs with a shell length of 95–100 mm (recruits) to the abundance of molluscs of commercial length of > 100 mm). The state of M. kurilensis population in Peter the Great Bay is stable: the ratio of molluscs of non-commercial length varies 52 to 86 % in most settlements, which indicates active natural reproduction and regular replenishment of the benthic part over many years. Replenishment of settlements with settling of both spat and yearlings depends on the presence of pelagic larvae in the plankton, while replenishment of the mature molluscs depends on favorable conditions for juvenile survival. In 2007–2018, the mean values of the indices of settling and maturation in M. kurilensis settlements in Peter the Great Bay were of (0.18 ± 0.07) and (0.05 ± 0.01), respectively. M. kurilensis resources are estimated at 27.1 thousand tons, and the commercial stock – at 16.4 thousand tons. The annual replenishment of the commercial stock of M. kurilensis in Peter the Great Bay is possible in a volume of more than 3 thousand tons. The mean value of the index of replenishment of the commercial stock is of (0.21 ± 0.03).

Potential impact of harvesting on Tanner crab (Chionoecetes bairdi) on state of its commercial stock off the coast of Kamchatka

Potential impact of landing on the stock and biological state of Tanner crab is analyzed for two fishery districts at Kamchatka in 2013-2020. In the Kamchatka-Kuril fishery subzone, the number of commercial males without limbs and with old shell increased in catches that may be associated with active operations of alive-crab vessels in 2015-2017. In the Petropavlovsk-Commander fishery subzone, cases of injured Tanner crabs catch became frequent after resumption of the crab harvesting in 2017, as well as the cases of commercial crabs with old shell, that also could be explained by operations of alive-crab vessels. The operations of such vessels are distinguished by strict sorting of caught crabs with removing the individuals of lower quality. As the result, the crabs without limbs and commercial males at late stages before molting were accumulated in the areas of sorting. The problem can be solved by measures for total registration (weighting) of catch before the start of sorting, concerning to all crabs with commercial size landed aboard. To avoid degradation of the Tanner crab population, development of catch processing aboard fishing vessels is recommended, with transportation of frozen products instead of live crabs.

Regioisomerization of Antimalarial Drug WR99210 Explains the Inactivity of a Commercial Stock

ABSTRACTWR99210, a former antimalarial drug candidate now widely used for the selection of Plasmodium transfectants, selectively targets the parasite’s dihydrofolate reductase thymidine synthase bifunctional enzyme (DHFR-TS) but not human DHFR, which is not fused with TS. Accordingly, WR99210 and plasmids expressing the human dhfr gene have become valued tools for the genetic modification of parasites in the laboratory. Concerns over the ineffectiveness of WR99210 from some sources encouraged us to investigate the biological and chemical differences of supplies from two different companies (compounds 1 and 2). Compound 1 proved effective at low nanomolar concentrations against Plasmodium falciparum parasites, whereas compound 2 was ineffective, even at micromolar concentrations. Intact and fragmented mass spectra indicated identical molecular formulae of the unprotonated (free base) structures of compounds 1 and 2; however, the compounds displayed differences by thin-layer chromatography, reverse-phase high-performance liquid chromatography, and UV-visible spectroscopy, indicating important isomeric differences. Structural evaluations by 1H, 13C, and 15N nuclear magnetic resonance spectroscopy confirmed compound 1 as WR99210 and compound 2 as a dihydrotriazine regioisomer. Induced fit computational docking models showed that compound 1 binds tightly and specifically in the P. falciparum DHFR active site, whereas compound 2 fits poorly to the active site in loose and varied orientations. Stocks and concentrates of WR99210 should be monitored for the presence of regioisomer 2, particularly when they are not supplied as the hydrochloride salt or are exposed to basic conditions that may promote rearrangement. Absorption spectroscopy can serve for assays of the unrearranged and rearranged triazines.

Features of allometric growth and structure of settlements for Mya uzenensis (Bivalvia: Myidae) in different areas of littoral zone in the Tauiskaya Guba Bay, Okhotsk Sea

Settlements of bivalve Mya uzenensis are investigated in four littoral areas of the Tauiskaya Guba Bay with different environments. Their density varied from 20 to 194 ind./m2 (518–9680 g/m2) depending on habitat. On suitable soils, the settlements occupied 25–40 % of the littoral zone; the mollusks were distributed mostly in mosaic spots with size 0.5–5.0 m2. Stable settlements in the areas with favorable environmental conditions in the Ola estuary and Vesyolaya Bay were formed by mollusks with shell size of 22.1–91.1 mm and age of 2–14 years. Allometry of the shells growth increased with age until 10 years, then leveled. The stocks of mollusk were assessed for certain areas that allowed to recommend for annual landing 158.4 t of M. uzenensis (7 % of commercial stock).

Current state of stock and fishery of red king crab Paralithodes camtschaticus at West Kamchatka

Current state of the red king crab population at West Kamchatka is considered on the data of bottom trawl surveys and fishery statistics since 2013. Some biological parameters of the crabs and assessments of the commercial stock are presented; recent condition of the red king crab fishery and evaluation of the total allowable catch are discussed. The red king crab fishery was resumed in 2013, after 8 years of ban caused by the population decrease. During the ban, the stock restored and exceeded the value observed before the ban: the total accounted abundance of red king crab in 2017 was about 244 . 106 ind. that was the highest level for the last two decades, with the number of commercial males estimated as 110 . 106 ind. — this amount was never observed before on the shelf of western Kamchatka, at least in four decades of surveys. Recently the northern forbidden district and Khayryuzovsky district of the shelf zone lost their role of the main areas of crabs reproduction and their juveniles feeding, in favour to the Ichinsky district located southward. Recent fishery of red king crab is fruitful and sustainable. In the last 3 years, the major part of annual catch is transported alive to ports of China and South Korea. For this purpose, the caught crabs are sorted strictly aboard fishing vessels and the largest males are released back to the sea. Possibly, year-to-year increasing of the males size on the West Kamchatka shelf is caused by this sorting and releasing; another effect of the large-sized crabs releasing is relatively low number of recruits in the last couple of years. The fishery elimination coefficient is estimated in the range 5–16 % of the total accounted stock for 2013–2019, that shows a highly precautionary approach. Gradual decreasing of the crab commercial stock is forecasted for the nearest future, though the stock will remain above the target value. Current state of the red king crab population at West Kamchatka is not considered as dangerous, and ongoing intense fishery of this valuable species within the recommended volumes will not affect this sustainable state.

Isomerization of antimalarial drug WR99210 explains its inactivity in a commercial stock

ABSTRACTWR99210, a former antimalarial drug candidate now widely used for the selection of Plasmodium transfectants, selectively targets the parasite dihydrofolate reductase thymidine synthase bifunctional enzyme (DHFR-TS) but not human DHFR, which is not fused with TS. Accordingly, WR99210 and plasmids expressing human dhfr have become valued tools for the genetic modification of parasites in the laboratory. Concerns over the ineffectiveness of WR99210 from some sources encouraged us to investigate the biological and chemical differences of supplies from two different companies (compounds 1 and 2). Compound 1 proved effective at low nanomolar concentrations against Plasmodium falciparum parasites, whereas compound 2 was ineffective even at micromolar concentrations. Intact and fragmented mass spectra indicated identical molecular formulae of the unprotonated (free base) structures of 1 and 2; however, the compounds displayed differences by thin layer chromatography, reverse phase high performance liquid chromatography, and ultraviolet-visible spectroscopy, indicating important isomeric differences. Structural evaluations by 1H, 13C, and 15N nuclear magnetic resonance spectroscopy confirmed 1 as WR99210 and 2 as an isomeric dihydrotriazine. Induced fit, computational docking models showed that 1 binds tightly and specifically in the P. falciparum DHFR active site whereas 2 fits poorly to the active site in loose and varied orientations. Stocks and concentrates of WR99210 should be monitored for the presence of isomer 2, particularly when they are not supplied as the hydrochloride salt or are exposed to basic conditions that can promote isomerization. Absorption spectroscopy may serve for assays of the unrearranged and rearranged triazines.