Parasite and genetic diversity of big-scale sand smelt (Atherina boyeri Risso, 1810) populations in their natural and expansion ranges in Ukraine.

The big-scale sand smelt (Atherina boyeri) is an Atlanto-Mediterranean amphidromous fish species found within the Black Sea. Here, we assess differences in the parasite fauna of big-scale sand smelt populations from their natural range in the northwestern Black Sea and from their expansion range in the Lower and Middle River Dnipro. In addition, we undertook a microsatellite analysis to assess the genetic similarity of fish from the different locations. We found that the parasite community of fish in their natural range was wider than that from their expansion range. While the Gulf of Odesa was most distant from all other localities by parasite community composition and the Dnipro Reservoir was characterised by an absence of parasites (newest and most distant expansion locality), only fish from the Danube Delta showed a significant genetic difference. Our results suggest that the parasite community of big-scale sand smelt is primarily influenced by environmental factors, such as habitat type, water salinity and/or prey composition. Both microsatellite analysis and parasite community species composition (e.g. the presence of the marine Telosentis exiguus in the Kakhovka Reservoir and freshwater Raphidascaris sp. in the Gulf of Odesa) confirmed that populations in the River Dnipro reservoirs had, at some time, been connected with native marine populations, thus also confirming the species' amphidromous nature.

Heteroalleles in Common Wheat: Multiple Differences between Allelic Variants of the Gli-B1 Locus.

The Gli-B1-encoded γ-gliadins and non-coding γ-gliadin DNA sequences for 15 different alleles of common wheat have been compared using seven tests: electrophoretic mobility (EM) and molecular weight (MW) of the encoded major γ-gliadin, restriction fragment length polymorphism patterns (RFLPs) (three different markers), Gli-B1-γ-gliadin-pseudogene known SNP markers (Single nucleotide polymorphisms) and sequencing the pseudogene GAG56B. It was discovered that encoded γ-gliadins, with contrasting EM, had similar MWs. However, seven allelic variants (designated from I to VII) differed among them in the other six tests: I (alleles Gli-B1i, k, m, o), II (Gli-B1n, q, s), III (Gli-B1b), IV (Gli-B1e, f, g), V (Gli-B1h), VI (Gli-B1d) and VII (Gli-B1a). Allele Gli-B1c (variant VIII) was identical to the alleles from group IV in four of the tests. Some tests might show a fine difference between alleles belonging to the same variant. Our results attest in favor of the independent origin of at least seven variants at the Gli-B1 locus that might originate from deeply diverged genotypes of the donor(s) of the B genome in hexaploid wheat and therefore might be called "heteroallelic". The donor's particularities at the Gli-B1 locus might be conserved since that time and decisively contribute to the current high genetic diversity of common wheat.

Toxic effect and genotoxicity of carvacrol ethers in Drosophila melanogaster.

The present study investigated the effect of four carvacrol ethers (propyl-, butyl, octyl- and benzyl) on the viability, level of dominant lethal mutations of Drosophila melanogaster and their influence on the multiplication of the nuclear genome in salivary gland cells. The fertility and viability of fruit flies were assessed after oral administration (0.05 % to culture medium) and inhalation exposure (5 mg per 1 cm2 of polyvinyl alcohol film) of compounds 1‒4 and initial carvacrol. The influence of terpenoid and its ethers on the degree of chromosomes polyteny in salivary gland cells of D. melanogaster larvae has been revealed. Among all tested compounds, carvacrol exhibited the most significant impact on frequency of dominant lethal mutations, fecundity and insect survival when inhaled or adding to the culture medium. Oral administration of ethers 1‒4 was found to decrease the average level of chromosome polyteny degree (366 C-500 C) while pure carvacrol adding to culture medium had the opposite effect (763 C) compared to control (695 C). The possible mechanism of action for carvacrol and its ethers is discussed.

Molecular markers in management of ex situ PGR-a case study.

Worldwide germplasm collections contain about 7.4 million accessions of plant genetic resources for food and agriculture. One of the 10 largest ex situ genebanks of our globe is located at the Leibniz Institute of Plant Genetics and Crop Plant Research in Gatersleben, Germany. Molecular tools have been used for various gene bank management practices including characterization and utilization of the germplasm. The results on genetic integrity of longterm- stored gene bank accessions of wheat (self-pollinating) and rye (open-pollinating) cereal crops revealed a high degree of identity for wheat. In contrast, the out-pollinating accessions of rye exhibited shifts in allele frequencies. The genetic diversity of wheat and barley germplasm collected at intervals of 40 to 50 years in comparable geographical regions showed qualitative rather than a quantitative change in diversity. The inter- and intraspecific variation of seed longevity was analysed and differences were detected. Genetic studies in barley, wheat and oilseed rape revealed numerous QTL, indicating the complex and quantitative nature of seed longevity. Some of the loci identified were in genomic regions that co-localize with genes determining agronomic traits such as spike architecture or biotic and abiotic stress response. Finally, a genome-wide association mapping analysis of a core collection of wheat for flowering time was performed using diversity array technology (DArT) markers. Maker trait associations were detected in genomic regions where major genes or QTL have been described earlier. In addition, new loci were also detected, providing opportunities to monitor genetic variation for crop improvement.

Genetic integrity of ex situ Genebank collections.

The genetic integrity of four accessions of the cross-pollinating species rye (Secale cereale L.) was investigated. Seeds available from the first and most recent regeneration cycles, multiplied 8, 12 (twice) or 14 times were fingerprinted using microsatellite markers. In all four accessions the allele numbers and frequencies changed after regeneration. Alleles present in the original seed sample were not detectable in the regenerated populations, whereas on the other hand, alleles were found in the recent seed sample, which were not observed in the investigated plants of the original one.