Isolation and structural analysis of a gene coding for a novel type of aspartic proteinase from buckwheat seed (Fagopyrum esculentum Moench)

Iz biblioteke cDNK semena heljde u srednjoj fazi razvića izolovan je gen koji kodira novi tip aspartične proteinaze. Analizom sekvence ove cDNK (Fe-APL1) uočeno je odsustvo domena karakterističnog samo za biljne aspartične proteinaze, a analizom odgovrajućeg genomskog fragmenta da se radi o genu koji ne sadrži introne. Bioinformatičkim analizama genoma arabidopsisa je pokazano da je većina potencijalnih gena za aspartične proteinaze upravo sa ovim osobinama, iako je to eksperimentalno dokazano samo kod malog broja gena. Rezultati ovog rada daju doprinos u analizi raznovrsnosti unutar familije biljnih aspartičnih proteinaza. .A novel type of aspartic proteinase gene was isolated from the cDNA library of developing buckwheat seeds. This cDNA, FeAPL1, encoded an AP-like protein lacking the plant-specific insert (PSI) domain characteristic of typical plant aspartic proteinases. In addition the corresponding genomic fragment was isolated. It is demonstrated that this gene does not contain introns. Since bioinformatics analysis of the Arabidopsis genome showed that most potential AP genes are intronless and PSI-less, it appears that "atypical" is an inappropriate word for that class of AP. Isolation of this specific buckwheat gene among the small group of those isolated from other plant species provides a new perspective on the diversity of AP family members in plants.

Seed-specific aspartic proteinase FeAP12 from buckwheat (Fagopyrum esculentum Moench)

Gen za aspartičnu proteinazu (FeAP12) je izolovan iz eDNA biblioteke semena heljde u razviću. Analiza izvedene amino kiselinske sekvence FeAP12 gena ukazuje na njenu visoku homologiju sa ostalim tipičnim biljnim aspartičnim proteinazama (AP) koje se odlikuju prisustvom biljno specifičnog inserta (plant specific insert PSI), jedinstvenog među AP. Pokazano je da gen FeAP12 nije eksprimiran u listu, korenu, stablu i cvetu, već da je iRNA za FeAP12 prisutna samo u semenu. Najveći nivo ekspresije ovog gena je uočen u ranim fazama razvića semena, što ukazuje na njegovu moguću ulogu u degradaciji nucelusa.Aspartic proteinase gene (FeAP12) has been isolated from the cDNA library of developing buckwheat seeds. Analysis of its deduced amino acid sequence showed that it resembled the structure and shared high homology with typical plant aspartic proteinases (AP) characterized by the presence of a plant-specific insert (PSI), unique among APs. It was shown that FeAP12 mRNA was not present in the leaves, roots, steam and flowers, but was seed-specifically expressed. Moreover, the highest levels of FeAP12 expression were observed in the early stages of seed development, therefore suggesting its potential role in nucellar degradation

Infrared and Raman spectra of LiV2O5 single crystals

The phonon dynamics of LiV2O5 single crystals is studied using infrared and Raman spectroscopy techniques. The infrared-active phonon frequencies and dielectric constants are obtained by oscillator fitting procedure of the reflectivity data measured at room temperature. The Raman scattering spectra are measured at room temperature and at T=10 K in all nonequivalent polarized configurations. The assignment of the phonons is done by comparing the infrared and Raman spectra of LiV2O5 and NaV2O5. The factor-group-analysis of the LiV2O5 crystal symmetry and of its constituent layers is performed to explain the symmetry properties of the observed modes. We concluded that layer symmetry dominates in the vibrational properties of this compound.Comment: 10 pages, 5 figure

A search of Brassica SI-involved orthologs in buckwheat leads to novel buckwheat sequence identification: MLPK possibly involved in SI response

Kod biljaka cvetnica postoje genetički određeni sistemi self-inkompatibilnosti (SI), koji sprečavaju samooprašivanje i ukrštanje u srodstvu održavajući genetičku raznovrsnost vrsta. SI se javlja u dva oblika, kao gametofitna i sporofitna SI, koje se razlikuju u načinu određivanja SI fenotipa polena - kod GSI je SI fenotip polena određen polenovim sopstvenim haploidnim genomom, dok je kod SSI određen dipolidnim genotipom majke biljke. SSI se javlja kao homomorfna (jedan tip cveta u biljaka jedne vrste) i heteromorfna (dva ili tri tipa cveta u biljaka jedne vrste). Heteromorfna SSI je u poređenju sa homomorfnom SSI i GSI izuzetno malo proučena i za sada je upoznavanje na molekularnom nivou tek započelo. Kod heljde je prisutna distilna heteromorfna SSI, o kojoj je sakupljeno dosta podataka na fiziološkom nivou, ali o kojoj za sada nema molekularnih podataka. Na osnovu fiziološke sličnosti SI odgovora biljaka rodova Brassica i Prunus sa tram i pin morfom heljde, respektivno, zatim na osnovu toga što postoje dokazi da slični biohemijski mehanizmi leže u osnovi različitih SI odgovora i na osnovu toga što i evolutivno udaljene SI vrste mogu posedovati iste ili slične predačke SI gene, mi smo odlučili da ispitamo prisustvo ortologih gena uključenih u SI odgovore Brassica i Prunus u genomu heljde. Upotrebom izrođenih prajmera dizajniranih na osnovu evolutivno očuvanih regiona SRK, SLG, SP11 i MLPK sekvenci Brassica rapa, kao i S-RNaza i SFB gena roda Prunus, dostupnih u NCBI bazi podataka, ispitano je prisustvo ortologa ovih gena u genomu heljde. Takođe je prisustvo S-RNaza ispitano u proteinskim izolatima neoprašenih i kompatibilno i inkompatibilno oprašenih tučkova heljde oba morfa. Rezultati su pokazali da nema ortologa SRK, SLG, SP11, kao ni S-RNaza i SFB u genomu heljde, ali da postoji MLPK ortolog kod heljde. Izvedena aminokiselinska sekvenca pokazala je 80 % sličnosti sa MLPKf2 sekvencom Brassica rapa i APK1A Arabidopsis thaliana, potvrđujući da su u pitanju ortolozi koji bi mogli da imaju i sličnu ulogu. Naš sledeći korak je dobijanje cele nukleotidne sekvence MLPK heljde uz is- pitivanje postojanja alternativnih mesta iskrajanja i određivanje nivoa ekspresije po tkivima, kao i ispitivanje moguće uloge u SI odgovoru heljde. Ovi odgovori omogućiće bolje upoznavanje heteromorfnih SSI sistema koji su još uvek u svojoj najranijoj fazi istraživanja i obezbediće podatke nužne za uvid u evoluciju SI sistema biljaka cvetnica. Najzad, rasvetljavanjem SSI sistema heljde, koja se koristi u ishrani, biće moguće genetički kontrolisati ukrštanje heljde i dobijanje linija sa željenim hranljivim i/ili fiziološkim osobinama.Self-incompatibility (SI) systems, gamethophytic (GSI) and sporophytic (SSI), prevent self-pollination in angiosperms. Buckwheat displays heteromorphic SSI, with pollination allowed only between different flower morphs - thrum and pin. The physiology of thrum and pin morph SI responses are entirely different, resembling homomorphic Brassica SSI and Prunus GSI responses, respectively. Considering angiosperm species may share ancestral SI genes, we examined the presence of Brassica and Prunus SI-involved gene orthologs in the buckwheat genome. We did not find evidence of SRK, SLG and SP11 Brassica or S-RNase and SFB Prunus orthologs in the buckwheat genome, but we found a Brassica MLPK ortholog. We report the partial nucleotide sequence of the buckwheat MLPK and discuss the possible implications of this finding

Thermopower in the strongly overdoped region of single-layer Bi2Sr2CuO6+d superconductor

The evolution of the thermoelectric power S(T) with doping, p, of single-layer Bi2Sr2CuO6+d ceramics in the strongly overdoped region is studied in detail. Analysis in term of drag and diffusion contributions indicates a departure of the diffusion from the T-linear metallic behavior. This effect is increased in the strongly overdoped range (p~0.2-0.28) and should reflect the proximity of some topological change.Comment: 4 pages, 4 figure

Seed-specific aspartic proteinase FeAP12 from buckwheat (Fagopyrum esculentum Moench)

Aspartic proteinase gene (FeAP12) has been isolated from the cDNA library of developing buckwheat seeds. Analysis of its deduced amino acid sequence showed that it resembled the structure and shared high homology with typical plant aspartic proteinases (AP) characterized by the presence of a plant-specific insert (PSI), unique among APs. It was shown that FeAP12 mRNA was not present in the leaves, roots, steam and flowers, but was seed-specifically expressed. Moreover, the highest levels of FeAP12 expression were observed in the early stages of seed development, therefore suggesting its potential role in nucellar degradation

Polarized far-infrared and Raman spectra of SrCuO2 single crystals

We measured polarized far-infrared reflectivity and Raman scattering spectra of SrCuO$_2$ single crystals. The frequencies for infrared-active modes were determined using an oscillator-fitting procedure of reflectivity data. The Raman spectra were measured at different temperatures using several laser energies $\omega_L$. In addition to eight of twelve Raman active modes, predicted by factor-group analysis, we observed a complex structure in the Raman spectra for polarization parallel to the {\bf c}-axis, which consists of Raman-allowed A$_g$ symmetry modes, and B$_{1u}$ LO infrared-active (Raman-forbidden) modes of the first and higher order as well as their combinations. The Raman-forbidden modes have a stronger intensity at higher $\omega_L$ than the Raman-allowed ones. In order to explain this resonance effect, we measured the dielectric function and optical reflection spectra of SrCuO$_2$ in the visible range. We show that the Raman-allowed A$_g$ symmetry modes are resonantly enhanced when a laser energy is close to $E_0$, while Raman-forbidden (IR-active) modes resonate strongly for laser line energies close to the electronic transition of higher energy gaps.Comment: to be published in Physica

Effects of constant anodal tDCS, oscillatory tDCS, and tACS on short-term associative memory

Different transcranial electric stimulation (tES) techniques showed promise for noninvasive neuromodulation of memory functions. However, previous studies yielded inconsistent effects, while only a few studies directly compared the effects of different types of stimulation. Thus, here we aim to directly contrast three types of tES in the enhancement of short-term associative memory (STAM), namely, constant anodal transcranial direct current stimulation (tDCS), oscillatory transcranial current stimulation (otDCS), and transcranial alternating current stimulation (tACS). Forty healthy right-handed volunteers (25 females, M = 25.15 ± 3.66 years) participated in the cross-over sham-controlled experiment. Participants underwent four experimental sessions in counterbalanced order (at least 7 days apart) in which they received: tDCS (1.5mA), otDCS at individual theta frequency (ITF, 4-8Hz) (1.5mA ± 0.5mA), tACS at ITF (0±1mA), or sham over the left posterior parietal cortex (P3, 10-20 International EEG system). The current was applied for 20min with 30s ramp-up and ramp-down periods. In the sham condition, the current was applied only at the beginning and at the end in a 30s rump up/down fashion. STAM was assessed during the stimulation, 3-4 minutes after the onset of the protocol. The STAM task was designed in four parallel forms and consisted of digit-color association sequences in which single-digits (0-9) were presented sequentially on the cards of different colors. Participants were instructed to try to remember each digit-color association. The sequence length varied between 3 (low-demand) to 5 stimuli (high-demand) and the sequences were presented in pre-randomized order. At the end of each sequence, the participants were presented with a cue i.e., one of the previously seen color cards and they needed to recall the digit that was presented on a given card. Results showed that relative to sham tDCS improved STAM in low- [F(1,39) = 7.39, p = .010, ηp2 = .16] as well as high demand sequences [F(1,39) = 4.71, p = .036, ηp2 = .11], while otDCS [F(1,39) = 4.79, p = .035, ηp2 = .11] and tACS [F(1,39) = 4.42, p = .042, ηp2 = .10] exclusively improved performance for high-demand sequences. The results indicate that different stimulation protocols potentially facilitate different cognitive processes. Namely, the effects of constant tDCS on STAM appear to be mediated by boosting the lower-level attention processes while the oscillatory protocols seem to directly promote associative binding

Transcranial electric stimulation over posterior parietal cortex and short-term associative memory – Differential effects of constant vs. theta frequency oscillatory stimulation

Transcranial electric stimulation (tES) techniques are promising tools for neuromodulation of memory functions. However, previous findings on their effectiveness are inconsistent, and there have been only a few studies directly contrasting different types of stimulation and examining their differential effects on memory performance. The study objective was the comparative assessment of the online effects of three types of tES over the left posterior parietal cortex (PPC) on the enhancement of short-term associative memory. The three tES types were constant anodal tDCS (1.5mA), and two types of personalized theta frequency (4-8Hz) oscillatory stimulation protocols - oscillatory tDCS (otDCS, 1.5mA ± 0.5mA) and tACS (0 ± 1mA). Participants (N = 40) took part in the sham-controlled cross-over experiment where they performed parallel forms of the short-term associative memory task while receiving different stimulation types in four counterbalanced experimental sessions (tDCS, otDCS, tACS, and sham). The stimuli within the short-term associative memory task consisted of digit-color association sequences in which single-digits (0-9) were presented sequentially on the cards of different colors. Participants were instructed to try to remember the digit-color associations presented in each sequence. The length of sequences varied between three (low-demand) to five stimuli (high-demand). At the end of each sequence, the participants were presented with one of the previously seen colored cards, and they needed to recall the digit that was presented on a given card. Planned contrasts within repeated-measures ANOVA showed that relative to sham constant anodal tDCS improved short-term associative memory for both low- and high-demand sequences, while two oscillatory protocols improved memory performance in high-demand sequences only. The results indicate that different stimulation protocols potentially affect different cognitive processes. Namely, the effects of constant anodal tDCS on cognitive performance seem to be mediated by the facilitation of low-level attention processes, while the effects of both otDCS and tACS appear to affect processes that are more central to the associative binding