Rearing river lamprey <Emphasis Type="Italic">Lampetra fluviatilis</Emphasis> (L.) larvae under controlled conditions as a tool for restitution of endangered populations

A method for actively protecting river lamprey and increasing the number of river lamprey populations is presented as protocol of rearing stocking material. The objective of the study was to accommodate lamprey larvae during the most critical life period under controlled conditions until they reach a sufficient size, which will increase their chances to survive in the natural environment. The eggs obtained from wild breeders were incubated in Weiss’s jars at the water temperature of 12 °C. The larvae were reared in tanks set up in closed recirculating aquaculture systems. During the rearing period, the water temperature was 20 °C and the density of larvae was 150 individuals per 1 dm² of bottom. In the initial rearing phase, the main focus was on the type of feeds and the nourishment method. It was determined that the most suitable feed type was Artemia nauplii combined with Hikari dry food. Additionally, the type of substrate was tested under controlled conditions. In this case, the optimum one was composed of sand of the grain size between 0.3 and 0.5 mm. The experiment proved that it is possible to successfully conduct river lamprey larvae rearing under controlled conditions. The growth rates are comparable to or better than those achieved under natural conditions. After 30 days of the rearing period, the lamprey larvae were 25 mm long. The results create a possibility to develop a technology for the restitution of river lamprey and other lamprey species, which are endangered throughout the world.     

Reactivity of selected markers of innate and adaptive immunity in rabbits experimentally infected with antigenic variants of RHD (Lagovirus europaeus/GI.1a)

Veterinary Research Communications - Lagovirus europaeus/GI.1 causes a fatal viral condition in rabbits characterized by acute viral hepatitis and disseminated intravascular coagulation. Due to...     

Meiotic gynogenesis affects the individual and gonadal development in sterlet Acipenser ruthenus

Larval growth and gonadal differentiation of gynogenetic sterlet Acipenser ruthenus were studied. The gynogenetic fish were produced by activation of albino sterlet eggs with UV‐irradiated sperm (collected from healthy coloration specimens), following by a heat shock of 34°C. Embryos were reared at 18.0 ± 0.5°C in a recirculation system and initially fed with Artemia sp. for 4 weeks and then fed with formulated feed. During the experiment, the length and weight of fish were recorded for the gynogenetic and control groups. Additionally, the analysis of gonadal sex differentiation was conducted with a 2‐week interval at 289, 303, 317, 331, 345 and 373 DPH. The mean body weight of the control group was significantly higher (p < .05) than the gynogenetic group only at 345 and 373 DPH, while the mean total body length was significantly higher at 331 and 345 DPH (p < .05). The gonad investigation was started at 289 DPH, and ~80% of females were found in the gynogenetic group during the trial period while the number of females and males was similar at 303, 331 and 373 DPH in the control group. The first symptoms of morphological differentiation appeared at 289 DPH, and the final shaping macroscopic structure of the gonad took place earlier in females than in males.     

Genetic variability of Polish tomato black ring virus isolates and their satellite RNAs

Tomato black ring virus (TBRV), a member of the Nepovirus genus, is a serious plant pathogen distributed worldwide. It causes significant damage to several economically important crops, such as artichoke or strawberry. The TBRV bipartite genome consists of two polyadenylated single-stranded positive-sense RNA molecules, which may be accompanied by subviral particles such as defective interfering RNAs (DI RNAs) and satellite RNAs (satRNAs). In this study, we obtained the complete genome sequence of six TBRV isolates originating from different hosts and determined the presence of eight TBRV satRNAs. Subsequently, genetic variability, recombination, phylogenetic and selection pressure analyses were performed. The results revealed that the TBRV population is genetically diverse. The occurrence of potential recombination events, evidence of positive selection pressure acting on particular codons and the diversification of satRNAs within the TBRV population indicated that the virus mutates and can rapidly adapt to new environmental conditions or hosts. The presented data shed some light on TBRV evolutionary dynamics and epidemiology.     

Fauna activity on soils developing on dead logs in an ancient inland temperate rainforest of North British Columbia (Canada)

Journal of Soils and Sediments - The aim of the study was to compare the feeding activity of soil fauna in forest floor soil and in soil layer developing on dead cedar logs in temperate ancient...     

Riboflavin content in the coelomocytes of contrasting earthworm species is differentially affected by edaphic variables including organic matter and metal content

The riboflavin content in extruded coelomocyte lysates derived from Dendrodrilus rubidus may serve as a sensitive bioindicator of soil metal pollution: the vitamin (B2) content has previously been found to be high in worms from unpolluted soil but low in worms inhabiting Zn/Pb mine soils, aerially deposited Ni-contaminated soil, and in worms experimentally transferred from clean soil to the metalliferous field soils. The aim of the present work was to extend these observations by comparing the number and riboflavin composition of coelomocytes retrieved from three lumbricid species (Allolobophora chlorotica, Dendrobaena veneta, Eisenia andrei) after 4-week exposures to an unpolluted commercial soil, two geochemically contrasting unpolluted field soils, and two different Zn/Pb/Cd-polluted soils from the Bukowno district in South Poland. Whilst eco-physiologically contrasting, these three earthworm species share the trait of possessing relatively high numbers of eleocytes, a category of immune-competent coelomocyte rich in autofluorescent riboflavin. Spectroflurometric analysis indicated that coelomocyte riboflavin content in worms maintained in strongly metalliferous soils or in unpolluted sandy-clay and loamy-sand soils was increased in coleomocytes from epigeic D. veneta and E. andrei species, whilst was decreased in endogeic A. chlorotica. In conclusion, the riboflavin content of earthworm coelomocytes is affected in species-specific ways by edaphic variables, including organic matter and metal pollution.     

HSPC117 is the essential subunit of a human tRNA splicing ligase complex

Splicing of mammalian precursor transfer RNA (tRNA) molecules involves two enzymatic steps. First, intron removal by the tRNA splicing endonuclease generates separate 5' and 3' exons. In animals, the second step predominantly entails direct exon ligation by an elusive RNA ligase. Using activity-guided purification of tRNA ligase from HeLa cell extracts, we identified HSPC117, a member of the UPF0027 (RtcB) family, as the essential subunit of a tRNA ligase complex. RNA interference-mediated depletion of HSPC117 inhibited maturation of intron-containing pre-tRNA both in vitro and in living cells. The high sequence conservation of HSPC117/RtcB proteins is suggestive of RNA ligase roles of this protein family in various organisms.