Rare species of cyclostomata and fish in the Upper Oka basin and within Kaluga oblast

The species list of fish of the Upper Oka basin is verified. Data on biology of rare species are presented (western brook lamprey Lampetra planeri, sterlet Acipenser ruthenus, bystryanka Alburnoides bipunctatus rossicus, asp Aspius aspius, undermouth Chondrostoma variabile, bitterling Rhodeus sericeus, and fresh-water sculpin Cottus gobio koshewnikowi). Their morphological characters, distribution in the Upper Oka basin relative abundances of these species, and its changes during recent decades are also commented.     

On the diversity of fishes in mountain lakes of the Amur basin

Results of the study of 11 lakes situated in the mountainous part of the Amur River basin are reported. Six fish species, namely, blunt-snouted lenok Brachymystax tumensis, Baikal-Lena grayling Thymallus baicalolenensis, Siberian stone loach Barbatula toni, Lagowski’s minnow Rhynchocypris lagowskii, Czekanowski’s minnow Rh. czekanowskii, and Amur sculpin Cottus szanaga, were found in five lakes. Four species were found in one lake (Lake Pereval’noe, basin of the Amgun’ River), and two species were found in each of the remaining lakes. Lenok and Amur sculpin were the most common species. The fauna of Lake Okonon (basin of the river Zeya) was the most specific and did not have analogs among the lake faunas; Czekanowski’s minnow and Baikal black grayling were found in this lake. The lenok ecotype that formed in the mountain lakes differed from the river lenok in some regards. The potential pathways of formation and protection of mountain lake ichthyocenoses of the Amur basin are discussed.     

Avoidance of host resistance in the oviposition-site preferences of rose bitterling

A contemporary outcome of dynamic host–parasite coevolution can be driven by the adaptation of a parasite to exploit its hosts at the population and species levels (parasite specialisation) or by local host adaptations leading to greater host resistance to sympatric parasite populations (host resistance). We tested the predominance of these two scenarios using cross-infection experiments with two geographically distant populations of the rose bitterling, Rhodeus ocellatus, a fish brood parasite of freshwater mussels, and four populations of their mussel hosts (two Anodonta woodiana and two Unio douglasiae populations) with varying degrees of geographic sympatry and local coexistence. Our data support predictions for host resistance at the species level but no effect of local coexistence between specific populations. Rhodeus ocellatus showed a preference for allopatric host populations, irrespective of host species. Host mussel response, in terms of ejection of R. ocellatus eggs, was stronger in the more widespread and abundant host species (A. woodiana) and this response tended to be higher in sympatric populations. These outcomes provide support for the importance of host resistance in bitterling oviposition-site decisions, demonstrating that host choice by R. ocellatus is adaptive by minimizing egg ejections. These findings imply that R. ocellatus, and potentially other bitterling species, may benefit from exploiting novel hosts, which may not possess appropriate adaptive responses to parasitism.     

Influence of roundup herbicide on the activities of peptidases in the intestines of various fish species

It has been revealed that, as a rule, Roundup herbicide inhibits activities of peptidases in the intestine mucosa and chyme in various fish species, both benthivorous (common carp Cyprinus carpio, silver bream Blicca bjoerkna, roach Rutilus rutilus, and crucian carp Carassius carassius) and piscivorous (perch Perca fluviatilis, pike Esox lucius, and sander Sander lucioperca). The tolerance of peptidases to the herbicide is species-specific. The magnitude and vector of the effects of Roundup depend on its concentration and localization of an enzyme. In the mucosa, the enzymes of common carp and pike are most tolerant, while the enzymes of common carp, silver bream, and pike are most tolerant in the chyme.     

Fish production in estuaries of Primorye

Production of fish communities in 15 different-types estuaries was assessed based on the data collected as a result of 90 surveys (860 seine stations) conducted in Primorye in 2002–2015. The main contribution to production was made by semi-anadromous species (the so-iuy mullet Liza haematocheilus, Far Eastern redfins Tribolodon spp., and Japanese smelt Hypomesus nipponensis, etc.). In both external (EP _ext) and internal (EP _int) polyhaline estuaries (EP) a substantial portion of the production was provided by resident marine species (mainly by the saffron cod Eleginus gracilis, Far Eastern smooth flounder Liopsetta pinnifasciata, and tidepool gunnel Pholis nebulosa) and southern immigrants (flathead grey mullet Mugil cephalus, dotted gizzard shad Konosirus punctatus, Japanese halfbeak Hyporhamphus sajori, and Pacific needlefish Strongylura anastomella). In mesohaline (EM) and oligohaline (EO) estuaries, the proportion of marine residents and southern immigrants was reduced to a minimum, while that of freshwater species (bighead gudgeon Gobio macrocephalus, Prussian carp Carassius gibelio, minnow Phoxinus spp., Amur bitterling Rhodeus sericeus, spiny bitterlings Acanthorhodeus spp., etc.) substantially added to the production of semi-anadromous fish. The mean fish biomass for the vegetation season varied in the 143–1463 mgC/m² range; the mean annual production was 174–4267 mgC/m² and the mean P/B ratio was 0.2–3.2. In 2007, the high annual production in the Artemovka River estuary, 9356 mgC/m², was formed by the juvenile so-iuy mullet of the strong yearclass that hatched in 2006. The lowest mean production and P/B values were typical mainly for the water bodies with a salinity more often close to that of the barrier zones (5–8‰ for α-horohalinicum and 22–26‰ for β-horohalinicum), i.e., for EM and EP _ext. This relationship is explained by the features of the osmotic regulation in fish of various origins and its ontogenetic variations. In particularly, the salinity in EM is more frequently close to the critical salinity (5–8‰, α-horohalinicum); thus, the proportion of juveniles of most of the species in the catches decreases (as their resistance to salinity variations is lower). This results in higher mean values of the specific and absolute production of fish communities in EP _int and EO as compared to those in EM. The conclusion was made that the estimates of fish production in the estuaries of Primorye are similar to those in the well-studied estuaries of the temperate, subtropical, and tropical zones. Moreover, they are comparable to the fish production estimates for mesotrophic and eutrophic lakes in northwestern Russia, substantially lower than those for large lowland rivers, and higher than those for small rivers. The fish production in seas, including the Japan/East Sea (0.20 gC/m²) and, particularly, Peter the Great Bay (0.28 gC/m²), is mostly lower than that in Primorye estuaries.     

Surface-attached and suspended bacterial community structure as affected by C/N ratios: relationship between bacteria and fish production

Bacteria play crucial roles in the combined system of substrate addition and C/N control, which has been demonstrated to improve aquaculture production. However, the complexity of surface-attached bacteria on substrates and suspended bacteria in the water column hamper further application of this system. This study firstly applied this combined system into the culture of grass carp, and then explored the relationship between microbial complexes from surface-attached and suspended bacteria in this system and the production of grass carp. In addition, this study investigated bacterial community structures as affected by four C/N ratios using Illumina sequencing technology. The results demonstrated that the weight gain rate and specific growth rate of grass carp in the CN20 group (C/N ratio 20:1) were the highest (P < 0.05), and dietary supplementation of the microbial complex had positive effects on the growth of grass carp (P < 0.05). Sequencing data revealed that, (1) the proportions of Verrucomicrobiae and Rhodobacter (surface-attached), sediminibacterium (suspended), and emticicia (surface-attached and suspended) were much higher in the CN20 group compared with those in the other groups (P < 0.05); (2) Rhodobacter, Flavobacterium, Acinetobacter, Pseudomonas, Planctomyces, and Cloacibacterium might be important for the microbial colonization on substrates; (3) as the C/N ratio increased, proportions of Hydrogenophaga (surface-attached and suspended), Zoogloea, and Flectobacillus (suspended) increased, but proportions of Bacillus, Clavibacter, and Cellvibro (surface-attached and suspended) decreased. In summary, a combined system of substrate addition and C/N control increased the production of grass carp, and Verrucomicrobiae and Rhodobacter in the surface-attached bacterial community were potential probiotic bacteria that contributed to the enhanced growth of grass carp.     

Tashkent riffle minnow <Emphasis Type="Italic">Alburnoides oblongus</Emphasis> belongs to the genus <Emphasis Type="Italic">Alburnus</Emphasis> (Osteichthyes: Cyprinidae) as inferred from mitochondrial and nuclear DNA markers

Sequences of mitochondrial (cytochrome b) and nuclear (recombination activating gene 1–RAG1) DNA markers were obtained for two species of the genus Alburnoides, the Taskent riffle minnow A. oblongus Bulgakov 1923 and the Terek spirlin A. gmelini Bogutskaya and Coad 2009. Phylogenetic analysis revealed that A. oblongus belongs to the genus Alburnus.     

Assessing the efficacy of corn-based bait containing antimycin-a to control common carp populations using laboratory and pond experiments

Strategic use of oral toxicants could allow for practical and sustainable control schemes for the invasive common carp (Cyprinus carpio, or ‘carp’) if a toxicant selectively targeted carp and not native species. In this study, we incorporated antimycin-a (ANT-A), a known fish toxicant, into a corn-based bait and conducted a series of experiments to determine its toxicity, leaching rate, and species-specificity. Our results showed that ANT-A was lethal to carp at doses ≥ 4 mg/kg and that the amount of ANT-A that leached out of the bait in 72 h was not lethal to carp or bluegill (Lepomis macrochirus). Species-specificity trials were conducted in 227 L tanks, in which carp were stocked with three native species representing families that occur sympatrically with carp in our study region: the fathead minnow (Pimephales promelas), yellow perch (Perca flavescens) and bluegill. These trials showed high mortality of carp (46%) and fathead minnows (76%) but no significant mortality of perch or bluegill. Finally, a pond study, which used the same species composition except for fathead minnows, resulted in 37% morality among adult carp and no mortality among perch or bluegill. Our results suggest that corn-based bait that contains ANT-A could be used to selectively control carp in ecosystems dominated by percids or centrarchids, such as lakes across the Great Plains ecoregion of North America, where carp are especially problematic.     

Food habits and relative abundances of native piscivores: implications for controlling common carp

Common carp (Cyprinus carpio, carp) are a widespread and ecologically destructive invasive fish species. Carp management is critical for maintaining healthy aquatic ecosystems, and many control options are available, but most have proven to be ineffective. Carp abundances have increased at The Nature Conservancy’s Emiquon Preserve, Illinois, since its restoration in 2007 despite management efforts to suppress this species. We conducted a comparative diet study in Illinois, Tennessee, and Wisconsin to test whether bowfin (Amia calva), spotted gar (Lepisosteus oculatus, gar), and largemouth bass (Micropterus salmoides) commonly preyed upon carp. We focused on bowfin and gar because they are hypoxia-tolerant, similar to carp. We also assessed whether specific fish community characteristics were correlated with carp relative abundances. We found no evidence that bowfin, gar, and bass consumed large numbers of carp. However, carp may be limited in some ecosystems (e.g., Reelfoot Lake, Tennessee) through alternative mechanisms associated with bowfin, gar, bass, and bluegill (Lepomis macrochirus) included in a diverse native fish community.     

Dynamics of species composition of fish and some results of ichthyomonitoring in the middle course of the Oka (Ryazan oblast)

The dynamics of species composition of fish from the middle course of the Oka is considered. A total of 53 species of Cyclostomata and fish was previously recorded; however, only 43 species have been found at the present time. Due to different causes, ten species have disappeared, and ten new species have emerged. The species composition and structure of aboriginal fish population are characterized by relative stability; however, the total abundance of fish during the current decade, as compared to the 1970s, has considerably decreased. The sterlet Acipenser ruthenus, lake minnow Phoxinus precnurus, Volga zander Sander volgensis, and freshwater sculpin Cottus gobio belong to rare fish.     

The endangered thick-shelled river mussel (<Emphasis Type="Italic">Unio crassus</Emphasis>): a new host species for the European bitterling (<Emphasis Type="Italic">Rhodeus amarus</Emphasis>)

Large freshwater mussels (Unionoida) are declining throughout the world. The European bitterling Rhodeus amarus (Bloch, 1782) female spawns its eggs inside the unionids’ shells, where fertilisation and further embryonic development take place; thus its reproduction depends fully on the presence of large freshwater mussels. Unio crassus, previously regarded as one of the most numerous unionids in Europe, is now listed in the IUCN Red Data List as being globally endangered. Despite its previous prevalence, it was never reported as a host for the bitterling. A large population of U. crassus was studied in small river at the ?wi?tokrzyskie Mts (Poland), where also electrofishing was conducted. In each bitterling territory located on the study plots, we found individuals of U. crassus, with the bitterling eggs or larvae developing on mussel’s gills. That proves that this species can be also used by the bitterling for reproduction. We suggest that this relationship has not been reported to date due to the mussels’ rarity and ongoing decline. However, it is also possible that the endangered mussel is a novel host for the bitterling, which is expanding its range throughout Europe.     

Constitutive expression of rice <Emphasis Type="Italic">ORGAN SIZE RELATED</Emphasis> genes in <Emphasis Type="Italic">Arabidopsis</Emphasis> results in organ size enlargement

In plants, organ size control is a fundamental process during development. The Arabidopsis ORGAN SIZE RELATED (OSR) gene family plays a key role in organ size regulation. To explore the roles of OSR orthologs in rice, a BLAST search in the rice genome was performed and five putative OSR orthologs were isolated and designated as OsOSR. Constitutive expression of OsOSR1, OsOSR2 and OsOSR4 in Arabidopsis resulted in enlarged organ sizes, as a consequence of enhanced cell number and cell size, while the increase of organ size in the OsOSR3 and OsOSR5-expressing plants was only due to cell enlargement. Our results suggest that the rice OsOSR genes possess the conserved organ growth-promoting function and may be involved in the coordination of cell proliferation and expansion during plant development.     

Organization of the olfactory system of the Indian major carp <Emphasis Type="Italic">Labeo rohita</Emphasis> (Ham.): A scanning and transmission electron microscopy study

Catla catla, Labeo rohita, and Cirrhinus mrigala represent important alimentary fish in India. Their reproduction/breeding depends on seasons. Fish perceive external factors-stimuli and chemical signals through the olfactory system that plays the key role in central regulation of reproduction. However, no electron microscopy data are available on organization of olfactory components of these fish. We studied organization of the olfactory organ in male L. rohita using scanning (SEM) and transmission electron microscopy (TEM). This organ consists of olfactory epithelium, a short nerve, and olfactory bulb. The olfactory organ is ovoid in shape and consists of about 47–52 lamellae in adults and about 14–20 lamellae in fingerlings. These lamellae originate from the midline raphe. By SEM, microvillar sensory and ciliated non-sensory cells were observed in the lamellae. TEM revealed microvillar receptor cell with rough endoplasmic reticulum and Golgi apparatus towards apical end. Basal cells were present at the base of receptor cell, supporting cells were located adjacent to the olfactory receptor neurons, while epithelial cells—in the nonsensory part of olfactory epithelium. Mast, blastema, and macrophage cells were also found at the basement membrane. This work is the first publication on ultrastructural organization of the olfactory system of the Indian major carp, which provides information about morphological and ultrastructural organization of the olfactory system and opens new avenues for further investigation of chemical neuroanatomy, sensory signal processing, and neural regulation of reproduction in the Indian major carp.     

Study on properties and regulation peculiarities of glycogenolysis enzymes in fish skeletal muscles depending on peculiarities of the species motor activity

The activity values, properties and peculiarities of activation of glycogen phosphorylase (GP, EC 2.4.1.1) and glycogen phosphorylase kinase (GPK, EC 2.7.138) were studied in the white skeletal muscle of fishes differing in motor behavior. No differences in the GP and GPK activity levels were revealed in porgy Diplodus annularis (L.), horse mackerel Trachurus mediterraneus ponticus, trout Salmo trutta morphario, scorpionfish Scorpaena porcus, flounder Scophtalnus maeoticus maeoticus, and carp Cyprinus carpio; however, properties of the isolated enzymes and peculiarities of formation of their activated forms during swimming in a hydrodynamic tube are determined by functional peculiarities of the muscle tissue and are associated with the motor activity character of the species. The more rapid ion regulation prevails in fishes capable for the burst swimming type (scorpionfish, trout). The glycogenolysis hormonal regulation leading to a change of the GPK activity index has been found in other species.     

Seasonal variations in bacterioplankton community structures in two small rivers in the Himi region of central Japan and their relationships with environmental factors

The aim of this study was to improve our understanding of seasonal variations and the effects of physicochemical conditions on the bacterioplankton communities in two small rivers, the Moo and Nakayachi Rivers in the Himi region of central Japan. These rivers are inhabited by unionid freshwater mussels, which are used for oviposition by the endangered Itasenpara bitterling (Acheilognathus longipinnis). Water samples were collected every month between March 2011 and February 2012. Changes in bacterioplankton community structures were analysed using an approach that did not require cultivating the bacteria and involved PCR and denaturing gradient gel electrophoresis. The bacterioplankton community structures in the two rivers were similar in all seasons except winter. The bacterial sequences identified were dominated by typical freshwater Actinobacteria, Bacteroidetes, Cyanobacteria, α-Proteobacteria, and β-Proteobacteria bacterioplankton. Many β-Proteobacteria species were detected in all seasons, but Bacteroidetes species were dominant in the winter. The bacterioplankton community structures were affected by biochemical oxygen demand, chemical oxygen demand, chlorophyll-a concentration, water depth, and water temperature. These results provide a foundation for a more detailed understanding of the conditions that provide a suitable unionid habitat.     

Host Plant Perception and Selection in the Sibling Species <Emphasis Type="Italic">Macrolophus melanotoma</Emphasis> and <Emphasis Type="Italic">Macrolophus pygmaeus</Emphasis> (Hemiptera: Miridae)

The electroantennogram responses (EAGs) of Macrolophus melanotoma and Macrolophus pygmaeus (Hemiptera: Miridae) exposed to volatile compounds (VOCs) of host and non-host plants were compared. The VOCs were identified by gas chromatography. Hosts and non-hosts eliciting similar EAGs were tested in olfactory assays against plants without a significant EAGs for the two Macrolophus species. No characteristic VOC profile was found for hosts and non-hosts. Terpenes predominated in many hosts and carboxylic acids in non-hosts, but no specific VOCs were characteristic of host plants. Significant EAGs (maximum deflection values in mV) were recorded in plants with very different VOC profiles, both hosts and non-hosts. The EAGs were higher for M. melanotoma than for M. pygmaeus, and were higher for males than for females. In M. melanotoma the EAGs were greater with hosts than with non-hosts, but they were similar in M. pygmaeus. The EAGs were correlated with the concentrations of sesquiterpenes and alcohols in both species. In olfactory assays, M. melanotoma and M. pygmaeus preferred their respective hosts, but they did not discriminate between non-host with and without significant EAGs. According to the results, Macrolophus species are expected to rely on ubiquitous VOCs for the identification of their hosts. The variation in the EAGs between M. melanotoma and M. pygmaeus is attributed to the variation in the proportions of olfactory receptor neurones with different sensitivity to VOCs (e.g. sesquiterpenes). Host plant selection is discussed in the light of the perception of VOCs and the processing of information by the central nervous system.     

The diversity of culturable yeasts in the phylloplane of rice in Thailand

One hundred and fifty-six yeast strains were obtained by the enrichment technique from the phylloplanes of 85 rice leaf samples collected from seven provinces in Thailand. On the basis of the D1/D2 domain of the large subunit rRNA gene sequence analysis, 156 strains were identified as 34 known species in 18 genera consisting of 25 species in 13 genera of the phylum Ascomycota and nine species in five genera of the phylum Basidiomycota. The species in the phylum Ascomycota comprised 24 species in 12 genera of the order Saccharomycetales and one species viz. Yarrowia lipolytica in Saccharomycetales incertae sedis. The 24 species viz. Candida glabrata in the Nakaseomyces clade of Saccharomycetaceae, Candida jaroonii, Candida membranifaciens and Candida terebra in the Yamadazyma clade of Debaryomycetaceae, Candida pseudolambica in the Pichia clade of Pichiaceae, Candida ruelliae in the Metschnikowia clade of Metschnikowiaceae, and three unaffiliated clade Candida species (Candida catenulata, Candida rugosa and Candida tropicalis); Clavispora lusitaniae, Kodamaea ohmeri, Metschnikowia koreensis and Metschnikowia lopburiensis in Metschnikowiaceae; Cyberlindnera fabianii, Cyberlindnera rhodanensis and Wickerhamomyces ciferrii in Wickerhamomycetaceae; Debaryomyces nepalensis, Meyerozyma caribbica, Meyerozyma guilliermondii, Millerozyma koratensis, and Yamadazyma mexicanum in Debaryomycetaceae; Pichia kudriavzevii in Pichiaceae; and Lachancea thermotolerans in Saccharomycetaceae. The species in Basidiomycota viz. Cryptococcus flavescens, Cryptococcus laurentii, Cryptococcus aff. laurentii and Cryptococcus rajasthanensis in the Tremellales lineage, Bulleromyces clade, Tremellales, Tremellomycetes, Agaricomycotina; Pseudozyma antarctica and Pseudozyma aphidis in Ustilaginales, Ustilaginomycetes, Ustilaginomycotina; Rhodotorula taiwanensis and Sporobolomyces blumeae in Sporidiobolales, Microbotryomycetes, Pucciniomycotina; and Trichosporon asahii in Trichosporonales, Tremellomycetes, Agaricomycotina. The most prevalent species was R. taiwanensis with a 23 % frequency of occurrence followed by Candida tropicalis (16 %) and Cryptococcus fabianii (12 %).     

Taste attractiveness of free amino acids and their physicochemical and biological properties (as exemplified by fishes)

Using fishes (32 species, 11 families) as an example, the relationship between the taste attractiveness of free amino acids (L-isomers) and their physicochemical and biological properties was analyzed. It was shown that essential amino acids, most nutritionally required for an organism, have lower taste attractiveness for fishes than nonessential amino acids. Only in 6 of the 32 tested species (sunbleak Leucaspius delineatus, European minnow Phoxinus phoxinus, dace Leuciscus leuciscus, chub Leuciscus cephalus, blue gourami Trichopodus trichopterus, pearl gourami Trichopodus leerii) the relationship between the taste attractiveness and molecular weight of amino acids was supported statistically, being negative in all cases. Only in 2 species, a statistically significant correlation between the taste properties of amino acids and the dissociation constant (K₁) was found, positive in the stone loach Barbatula barbatula and negative in the lake char Salvelinus namaycush. A positive correlation between taste preferences and the magnitude of the isoelectric point (pI) of amino acids was found in one species (roach Rutilus rutilus) and a negative correlation in 2 species (brown trout Salmo trutta and Arctic char Salvelinus alpinus erythrinus). A statistically significant correlation between the taste attractiveness and water solubility of amino acids was revealed in 2 species (chum salmon Oncorhynchus keta and navaga Eleginus nawaga), negative in both cases. The flavor, which stimulates food intake, was found to be more often intrinsic to acidic and polar uncharged than basic and nonpolar amino acids, L- than D-isomers, amino acids with an amino group at the α- than β-position. Amino acids are more attractive than their salts. Aromatic amino acids are much less attractive than S-containing or acyclic amino acids. Thus, in most fish species there is no or weak relationship between the taste attractiveness of free amino acids and many of their physical, chemical and biological properties, suggesting a mediated character of this relationship and/or its poor detectability.