Plants exposed to stress use the variety of gene regulatory mechanisms to achieve cellular homeostasis, including posttranscriptional regulation of gene expression where microRNAs (miRNAs) play a pivotal role. Since various environmental stress factors such as nanoparticles affect crop productivity and quality, the aim of the present study was to evaluate the genotoxicity level and to estimate miRNA expression level and chlorophyll a level in the magnetite (Fe3O4) nanoparticle-stressed rocket (Eruca sativa Mill.) seedlings grown in hydroponics. Rocket seedlings were exposed to 1 mg/L, 2 mg/L, and 4 mg/L Fe3O4 nanoparticles, and after 5 weeks, seed germination rate, root-shoot elongation, genotoxicity, chlorophyll a, and miRNA expression levels were evaluated. The obtained results indicated that 1 mg/L, 2 mg/L, and 4 mg/L concentrations of Fe3O4 nanoparticles induce low genotoxicity and have a positive effect on the growth and development of rocket seedlings and that nanoparticles may improve the ability of plants to stand against environmental stresses.

Nanoparticles influence on genome is investigated worldwide. The appearance of somaclonal variation is a cause of great concern for any micropropagation system. Somaclonal variation describes the tissue-culture-induced phenotypic and genotypic variations. This paper shows the results of somaclonal variation in two resistance genes pectin methylesterase and Mlo-like protein in all tissue culture development stages, as donor plant, calluses, and regenerants of Linum usitatissimum induced by gold and silver nanoparticles. In this paper, it was essential to obtain DNA material from all tissue culture development stages from one donor plant to record changes in each nucleotide sequence. Gene region specific primers were developed for resistance genes such as Mlo and Pme3 to define the genetic variability in tissue culture of L. usitatissimum. In recent years, utilization of gold and silver nanoparticles in tissue culture is increased and the mechanisms of changes in genome induced by nanoparticles still remain unclear. Obtained data show the somaclonal variation increase in calluses obtained from one donor plant and grown on medium supplemented by gold nanoparticles (Mlo 14.68 ± 0.98; Pme3 2.07 ± 0.87) or silver nanoparticles (Mlo 12.01 ± 0.43; Pme3 10.04 ± 0.46) and decrease in regenerants. Morphological parameters of calluses showed a number of differences between each investigated culture group.

Scientific information on amphipods and other peracaridan crustaceans in Latvian inland waters is insufficient. Therefore investigations of these animals are indispensable, especially because of the ongoing biological invasions of Ponto-Caspian amphipods causing changes in macroinvertebrate assemblages. Our recent investigation revealed that the alien amphipod Gammarus varsoviensis dominates amphipods in the upper courses of the Daugava River, whereas the other alien amphipod Pontogammarus robustoides prevails in the lower reaches of the river. Both these Ponto-Caspian amphipods were found co-occurring with the indigenous Gammarus pulex in the middle course of the Daugava River upstream from the Pļaviņas Reservoir. We predict that in the future the indigenous G. pulex will be fully exterminated by alien amphipods in the Latvian part of the Daugava River.

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The Latvian population of the Forest Dormouse is small and isolated, situated far from the main distribution range of this species. The population is located in the south-eastern region of Latvia, close to the Belarusian border. Sixty-three nest-boxes were located throughout this distribution area and captured forest dormouse individuals were sampled for genetic analysis. Animal age, sex, and coordinates from place of capture were recorded. DNA was extracted from 120 individuals using the QIAamp DNA Mini Kit (Qiagen, Germany). RAPD-PCR polymorphisms at 65 loci were used to examine the genetic diversity and differentiation of the Forest Dormouse population in Latvia. 89% of loci were polymorphic, average expected heterozygosity over all loci was 0.321, average polymorphism information content (PIC) was 0.246. The program ‘Structure’ was used to perform Bayesian assignment of individuals to a predefined number of clusters. The deltaK method identified that the most likely number of clusters within the Latvian Forest Dormouse population was three. Assignment of individuals to a particular cluster mostly corresponded with the location where the individual was captured. Analysis of molecular variance (AMOVA) indicated that there was significant genetic differentiation between the three clusters with pairwise Phipt (a modification of Fst) values ranging from 0.118 to 0.180.