Case Study of Somaclonal Variation in Resistance Genes Mlo and Pme3 in Flaxseed (Linum usitatissimum L.) Induced by Nanoparticles.

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.

High prevalence of Trichinella spp. in sylvatic carnivore mammals of Latvia.

Trichinella spp. are zoonotic parasites transmitted to humans by the consumption of raw or insufficiently cooked meat of different animal species. Carnivore mammals are important reservoir hosts of these nematodes. The aims of this work were to establish the prevalence of Trichinella spp. and infection intensity in sylvatic carnivore mammals of Latvia, to identify the etiological agents at the species level and their circulation in the Latvian regions. From 2010 to 2014, muscle samples were collected from 1286 hunted animals (2 European badgers, 137 pine martens, 24 stone martens, 4 golden jackals, 394 raccoon dogs, 668 red foxes, 23 grey wolves, and 34 Eurasian lynxes). Trichinella spp. larvae were isolated by muscle digestion. Overall, 633 animals (49.2%; 95% CI 46.5%-52.0%) belonging to all the eight investigated species, tested positive for Trichinella spp. larvae. Trichinella britovi was the most common species (94.0%; 95% CI 91.7%-95.7%). Trichinella nativa was detected in 30 animals as single (6, 1.1%; 95% CI 0.4%-2.3%) or mixed infection (24, 4.4%; 95% CI 2.9%-6.4%) with T. britovi. Trichinella spiralis was detected in only three animals as mixed infection with T. britovi. The high prevalence of Trichinella spp. infection in sylvatic carnivore mammals suggests that they are good indicators for the risk assessment of Trichinella spp. in Latvia.

A 38-year study on Trichinella spp. in wild boar (Sus scrofa) of Latvia shows a stable incidence with an increased parasite biomass in the last decade.

BACKGROUND: Trichinella spp. are zoonotic parasites transmitted to humans by the consumption of raw or insufficiently cooked meat of different animal species. The most common source of infection for humans is meat from pigs and wild boar (Sus scrofa). The aim of the present work was to evaluate the incidence of Trichinella spp. infections in wild boar hunted in Latvia over a 38 year interval (1976 to 2013). METHODS: A total 120,609 wild boars were individually tested for Trichinella spp. by trichinoscopy and, in case of negativity, by artificial digestion of 25 g muscles, in the 1976-2005 period, and by artificial digestion of 25-50 g muscles in the 2006-2013 period. Trichinella spp. larvae were identified at the species level by multiplex PCR. RESULTS: In the study period, the overall prevalence of infected wild boar was 2.5%. Trichinella britovi was the predominant (90%) species. The incidence of Trichinella spp. infection in wild boar exhibited two different trends. From 1976 to 1987, the incidence of infected/hunted wild boar increased from 0.23% to 2.56%, then it decreased to 0.19 in 1994. Thereafter, the incidence fluctuated between 0.05% and 0.37%. A statistically significant (P < 0.05) correlation (r = 0.54; p = 0.0199) was found between the trend of Trichinella spp. incidence in hunted wild boar and the number of snow cover days from 1976 to 1993. From 1997 to 2013, the estimated wild boar population of Latvia increased by 4.9 times and the hunting bag by 9.7 times, with a stable incidence of Trichinella spp. in the population. It follows that the biomass of Trichinella spp. larvae and of T. britovi, in particular, increased. CONCLUSIONS: The incidence trends of Trichinella spp. in wild boar could be related to the role played by the snow in reducing the thermal shock and muscle putrefaction which increases the survival of the larvae in muscle tissues of carrion in the 1976-1993 period; and, in the 1997-2013 period, to the increased biomass of Trichinella spp. due to the increased carnivore populations, which are the main reservoirs of these parasites.