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Featured researches published by Isaak Rashal.
Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences | 2012
Inese Kokina; Ēriks Sļedevskis; Vjaceslavs Gerbreders; Dace Grauda; Marija Jermaļonoka; Kristīna Valaine; Inese Gavarāne; Inga Pigiņka; Maksims Filipovičs; Isaak Rashal
Frequency of callusogenesis, type and capacity of regeneration, cell ploidy, DNA methylation level, histological features, autofluorescence and photobleaching effects were studied in flax calli grown on medium supplemented with different concentrations of carbon (C) nanoparticles. The presence of carbon nanoparticles on medium decreased the percentage calli formation. Detailed histological study led to better understanding of changes in calli caused by nanoparticles. Ploidy variation in calli cells significantly depended on carbon nanoparticle concentration in the medium. Different types of calli regeneration associated with different C nanoparticles concentration in medium were observed: somatic embryogenesis (direct or indirect) or organogenesis. C nanoparticle dose-dependent DNA hypermethylation in flax calli cells were found. Increased repair ability during laser irradiation was found in calli grown on medium with carbon nanoparticles
Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences. | 2014
Dace Grauda; Andra Miķelsone; Nadežda Ļisina; Kârlis Žagata; Reinis Ornicāns; Oksana Fokina; Lita Lapiņa; Isaak Rashal
Abstract Our goal was to improve the method of obtaining double haploids (DH) by anther culture from Latvian breeding material for several agriculturally important cereals in Latvia: barley, spring and winter wheat. Hybrids from Latvian breeders were initial material. It was found that copper (2.5 mg/l) added to barley anther pre-treatment media and to both barley (C3) and wheat (liquid AMC) induction media, resulted in a higher percentage of green plants-regenerants. In general, the winter wheat hybrids exhibited lower embryogenesis than spring wheat hybrids. Obtaining a large number of DH lines from barley and wheat hybrids with unknown androgenesis response can be organized in two stages: first - selection from breeding initial material hybrids responsive in anther culture, which enables production of green plants-regenerants, and second - production of DH lines in a large scale from selected hybrids. Abstract Darba mçríis bija uzlabot dubultoto haploîdu (DH) lîniju iegûðanas metodiku ar putekðnîcu kultûru palîdzîbu Latvijâ svarîgiem graudaugiem: mieþiem, vasaras un ziemas kvieðiem. Kâ izejas materiâls pçtîjumam kalpoja F1 un F2 paaudzes selekcionâru iegûtie hibrîdi. Pçtîjuma rezultâti parâdîja, ka vara sulfâta pievienoðana koncentrâcijâ 2,5 mg/l mieþu pirmapstrâdes barotnei un gan mieþu (C3), gan kvieðu (ðíidrâ AMC) kallusu indukcijas barotnçm paaugstina zaïo augu-reìenerantu iznâkumu. Liela skaita DH lîniju iegûðanu ar putekðnîcu kultûras palîdzîbu var organizçt divos etapos: pirmajâ nosaka hibrîdu atsaucîbu putekðnîcu kultûrâ un otrajâ masveidâ izmanto tikai atlasîtos hibrîdus ar augstu spçju veidot zaïus augus-reìenerantus
Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences. | 2012
Inese Kokina; Isaak Rashal
Results of monitoring of the population of Blumeria graminis f.sp. hordei in Latvia in 2009-2010 In 2009-2010, random samples of the causal agent of barley powdery mildew were collected in Daugavpils (south-eastern Latvia, Latgale region), Stende (north-western Latvia, Kurzeme region) and Priekuļi (north-eastern Latvia, Vidzeme region). Virulence frequency, complexity and pathotypes were calculated in the pathogen populations. Significant differences of virulence detected by the genes Va1, Va3 and Va13 occurred among samples of the pathogen population collected in different parts of Latvia. Nei index, Müllers index, Kosman index, Shannon index and Simpson index showed considerably higher diversity in Daugavpils and Stende during 2009-2010. In Daugavpils, the population of Blumeria graminis f.sp. hordei was particularly characterised by high diversity. Miežu miltrasas izsraisītāja Blumeria graminis f.sp. hordei populācijas monitorings Latvijā, 2009-2010 Miežu miltrasas izraisītāja paraugi tika ievākti 2009.-2010. gadā. Daugavpils apkārtnē (Latgale), Stendē (Kurzeme) un Priekuļos (Vidzeme). Katrā populācijā noteiktas patogēna virulences gēnu frekvences, virulences gēnu skaits katram individuālajam izolātam un patotipi. Ievērojamas frekvenču atšķirības starp populācijām konstatētas virulences gēniem Va1, Va3 un Va13. Populāciju raksturojošie rādītāji (Neja, Millera, Kosmana, Šenona un Simpsona indeksi) liecina par ievērojamu daudzveidības palielināšanos Latgalē un Kurzemē pētījuma laikā. Daugavpils apkārtnē ievāktajiem paraugiem tika konstatēta īpaši liela patotipu daudzveidība.
Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences. | 2015
Dace Grauda; Kalvis Avotiņš; Oksana Fokina; Agnese Kolodinska-Brantestam; Isaak Rashal
Abstract White clover (Trifolium repens L.) is well represented in the urban environment and wide areas. The goal of this study was to compare the genetic features and to determine the genetic distances and similarities between some populations of white clover using iPBS (inter primer binding sites) technique in a retrotransposon-based method in samples from ecologically different areas in Latvia. Comparisons were made between three plant groups: urban environment (different areas in Rīga), Latvian countryside territory (four different localities), and the commercial variety ‘Daile’. The Shannon diversity index was not high (0.2974 for Rīga, 0.3079 in countryside territories, and 0.3367 for the variety ‘Daile’), but the polymorphic bands present in all evaluated plant sets were higher than 89%. Using principal coordinates analysis the white clover formed three clusters. One cluster included plants from the variety ‘Daile’. The plants from Rīga urban area and different sites of Latvia formed two clusters. Baltais āboliņš (Trifolium repens L.) ir tauriņziežu dzimtas augs, plaši izplatīts gan pilsētvidē, gan ārpus tās. Tas tiek izmantots kā lauksaimniecības augs biomasas iegūšanai, un tā ir arī populāra daudzgadīgos zālienus veidojošā suga - pilsētvidē balto āboliņu sēj zālājos. Baltais āboliņš plaši pārstāvēts dažādos biotopos ar mainīgu ārējo faktoru ietekmi, tai skaitā pilsētvidē. Tādēļ tas ir piemērots modeļobjekts antropogēnās ietekmes pētīšanai. Darba mērķis bija noteikt baltā āboliņa Latvijas populācijas ģenētisko daudzveidību, izmantojot iPBS (inter primer binding sites) - uz retrotranspazoniem balstītu metodi. Iegūtie rezultāti salīdzināti starp trim augu paraugkopām: pilsētvidē augoši augi (Rīgas pilsētas teritorija), dabiskā vide (Latvijas novadu teritorijas) un selekcionētā šķirne Daile. Lai gan polimorfo lokusu skaits visās pētītajās grupās bija augsts (89%), tomēr Šanona (Shannon) indekss, kas raksturo grupu iekšējo ģenētisko daudzveidību, pētāmajām grupām svārstījās tikai ap 0.3. Šāds rezultāts norāda uz to, ka iekšējo grupu polimorfismu nosaka neliels ģenētiski atšķirīgu augu skaits. Galveno koordināšu analīzē, kas balstīta uz Šanona indeksu, visi pētītie paraugi izveidoja trīs grupas. Vienā no tiem grupējās šķirnes Daile augi, savukārt baltais āboliņš no pilsētvides un Latvijas reģioniem izveidoja divas atšķirīgas grupas.
Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences. | 2015
Dace Grauda; Lada Bumbure; Inga Lyashenko; Alexei Katashev; Yuri Dekhtyar; Isaak Rashal
Abstract The unique biological properties of amber are well known. Amber particles that penetrate into the cellular matrix can potentially be used as markers of plant cell biological activity by identification of living cells in flow cytometry. However, there have been no studies on effect of amber particles on plant cells. The aim of this study was to determine effect of amber nano- and micro- (5 nm-3 μm) particles on somatic and gametic cells and to assess the possibility to use amber particles as alive plant cells markers. To reach the aim, fluorescence of cells was determined in the presence of amber particles, and amber components - spirit of amber and sodium succinate dibasic hexahydrate. Cell fluorescence was measured using a BD FACSJazz® cell sorter for several plants species (Argyranthemum frutescens, Cyclamen persicum, Hordeum vulgare and Linum usitatissimum) with and without treatment of amber. Differences between a control cell group (without amber treatment) and treated cell group with amber particles depended on plant species. The presence of amber components (alcohol soluble amber fraction and sodium succinate) in cultivation media mostly had no influence on cell fluorescence. The study showed that amber particles (size 5 nm-3 μm) can be used as living plant cell markers, as the presence of amber particles in plant cell cultivation media resulted in substantially increased plant cell fluorescence in all investigated species, and there was no detrimental effect of amber particles on plant cells. Labi zināma ir dzintara labvēlīgā ietekme uz dažādiem organismiem, tomēr ir ļoti maz pētījumu par dzintara ietekmi uz augu šūnām. Tādēļ šī pētījuma mērķis bija noskaidrot nano un mikro lieluma (5 nm-3 μm) dzintara daļiņu un dzintara komponentu (spirtā šķīstošā dzintara frakcija un sukcināta) ietekmi uz augu somatiskajām un gametiskajām šūnām, un noskaidrot dzintara daļiņu piemērotību dzīvu augu šūnu iezīmēšanai urbānās vides pētījumiem, izmantojot plūsmas citometriju. Relatīvā fluorescence, izmantojot BD FACSJazz® šūnu šķirotāju ar plūsmas citometra funkciju, tika noteikta èetru dažādu ģinšu sugu (Argyranthemum frutescens, Cyclamen persicum, Hordeum vulgare, Linum usitatissimum) augu šūnām pēc 2 un 24 stundu kultivācijas barotnēs ar un bez dzintara daļiņām vai dzintara komponentiem. Konstatēts, ka dzintara daļiņu klātbūtne visām pētīto augu šūnām ievērojami palielināja relatīvo fluorescenci. Dzintara komponentu ietekme uz šūnu relatīvās fluorescences izmaiņām nebija būtiska, salīdzinot ar dzintara daļiņu ietekmi. Dzintara daļiņas nesamazināja dzīvo šūnu daudzumu paraugos. Konstatēts, ka dzintara daļiņas (5 nm-3 μm) var izmantot kā marķierus dzīvo šūnu iezīmēšanai plūsmas citometrijas pētījumos.
Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences. | 2015
Dace Grauda; Anton Kolodynski; Inta Belogrudova; Lada Bumbure; Isaak Rashal
Abstract The paper presents the results of combined effects of an extremely low frequency electromagnetic field (50 Hz) (ELF EMF) and SiO2 nanoparticles on fluorescence of plant gametic cells (immature microspores). The data were recorded by a BD FACSJazz® cell sorter after cell irradiation by blue laser (488 nm). A significant difference of fluorescence was observed between gametic cells after 1 hour incubation in suspension of SiO2 nanoparticles and the control gametic cells. It was observed that fluorescence intensity of gametic cell was higher with ELF EMF treatment in comparison to control cells, but it was statistically significant only for cells treated with electromagnetic radiation field with density 100 μT (ρ < 0.01) and 400 μT (ρ < 0.01). A different effect of ELF EMF were observed in cells incubated in SiO2 nanoparticle suspension; interaction of the factors resulted in lower cell fluorescence in comparison to control cells. The present study showed that SiO2 nanoparticles may be a source of oxidative stress, but jointly with 50 Hz electromagnetic field they can serve as an efficient antioxidant Urbānajā vidē dzīvie organismi atrodas nepārtrauktā saskarē ar dažāda veida piesārņojumu. Gan zemfrekvences elektromagnētiskais lauks (ZF EML), gan SiO2 nanodaļiņas ir vispārzināmi urbānās vides piesārņojuma veidi. Kombinēta zemferekvences elektromagnētiskā lauka un SiO2 ietekme uz šūnām ir maz pētīta. Šī pētījuma mērķis bija noteikt ZF EML un bioloģiski aktīvu (diametrā mazākas par 20 nm) SiO2 nanodaļiņu ietekmi uz augu gametiskajām šūnām. Kā modeļa objekts pētījumā tika izmantotas Cyclamen persicum gametiskās šūnas vienkodola attīstības stadijā. Gametiskās šūnas tika kultivētas MS barotnē. Pirms ievietošanas ZF EML šūnas 1 h tika inkubētas barotnē, kam pievienoja SiO2 nanodaļiņu suspensiju (1 mg/10 ml). Šūnas tika apstrādātas ZF EML 50 Hz ar blīvumu 50, 100, 200 un 400 μT. Šūnu relatīvās fluorescences izmaiņas tika noteiktas ar plūsmas citometru (BD FACSJazz®). Parādīts, ka gan SiO2 klātūtne kultivācijas barotnē gan šūnu ievietošana ZF EML statistiski ticami palielina gametisko šūnu fluorescenci. Šūnu apstrāde ar ZF EML, pēc to inkubācijas SiO2 nanodaļiņu suspensijā, statitiski ticami samazināja šūnu relatīvo fluorescenci. Rakstā tiek apspriesti iespējamie šāda efekta iemesli
Archive | 2004
Inese Kokina; Isaak Rashal
Archive | 2012
Inta Belogrudova; Dace Grauda; Gunta Jakobsone; Isaak Rashal
Archive | 2005
Inese Kokina; Isaak Rashal
Acta Biologica Universitatis Daugavpiliensis | 2009
Dace Grauda; Inese Kokina; Isaak Rashal