Transcriptional profiling of catalase genes in juglone-treated seeds of maize (Zea mays L.) and wheat (Triticum aestivum L.)

The major aim of the present study was to investigate the influence of juglone (JU; 5-hydroxy-1,4 naphthoquinone) treatments on the expression level of Cat1, Cat2 and Cat3 genes, encoding the respective catalase isozymes in maize (Zea mays L.) and wheat (Triticum aestivum L.) seeds. In parallel, germination efficiency, catalase (CAT) activity and hydrogen peroxide (H2O2) content in juglone-exposed cereal seeds were assessed. Juglone applications significantly stimulated abundance of three target catalase transcripts as well as induced CAT activity and generation of H2O2 in both maize and wheat kernels. Furthermore, germination process of juglone-affected maize seeds was more severe suppressed than in case of wheat kernels. The role of juglone in triggering the oxidative stress as well as antioxidative responses in seeds of the studied model cereal species are discussed

CHLOROPHYLL CONTENT OF APHID-INFESTED SEEDLING LEAVES OF FIFTEEN MAIZE GENOTYPES

We measured the total chlorophyll (Chl a+b) content in seedling leaves of fifteen maize cultivars infested by two studied aphid species (oligophagous Rhopalosiphum padi L., monophagous Sitobion avenae F.) 7 and 14 days after the beginning of infestation, using a SPAD-502 chlorophyll meter. Chlorophyll loss was more severe in R. padi-infested than in S. avenae-infested plants. Chlorophyll depletion was greater after long-term (14 days) than after short-term aphid infestation in the investigated host systems. Seedlings of Złota Karłowa and Tasty Sweet were more damaged by aphid feeding; Ambrozja and Płomyk plants were less damaged by aphid feeding

Biochemical characterisation of chlorophyllase from leaves of selected Prunus species — A comparative study

Despite senescence-induced chlorophyll depletion in plants has been widely studied, the enzymatic background of this physiologically regulated process still remains highly unclear. The purpose of this study was to determine selected biochemical properties of partially purified fractions of chlorophyllase (Chlase, chlorophyll chlorophyllido-hydrolase, EC 3.1.1.14) from leaves of three Prunus species: bird cherry (Prunus padus L.), European plum (Prunus domestica L.), and sour cherry (Prunus cerasus L.). Secondarily, this report was aimed at comparing seasonal dynamics of Chlase activity and chlorophyll a (Chl a) content within investigated plant systems. Molecular weight of native Chlase F1 has been estimated at 90 kDa (bird cherry) and approximately 100 kDa (European plum and sour cherry), whereas molecular mass of Chlase F2 varied from 35 kDa (European plum) to 60 kDa (sour cherry). Furthermore, enzyme fractions possessed similar optimal pH values ranging from 7.6 to 8.0. It was found that among a broad panel of tested metal ions, Hg +2, Fe +2, and Cu +2 cations showed the most pronounced inhibitory effect on the activity of Chlase. In contrast, the presence of Mg +2 ions influenced a subtle stimulation of the enzymatic activity. Importantly, although Chlase activity was negatively correlated with the amount of Chl a in leaves of examined Prunus species, detailed comparative analyses revealed an incidental decrement of enzymatic activity in early or moderately senescing leaves. It provides evidence that foliar Chlase is not the only enzyme involved in autumnal chlorophyll breakdown and further in-depth studies elucidating this catabolic process are required. Key words: chlorophyllase; chlorophyll catabolism; leaf senescence

Antimicrobial activity of five essential oils from lamiaceae against multidrug-resistant <i>Staphylococcus aureus</i>

<p>Analysis of Lamiaceae essential oils (EOs) by GC-FID-MS revealed the presence as the major constituents of linalool (16.8%), linalyl acetate (15.7%) in <i>Lavandula angustifolia</i>, menthol (29.0%), menthone (22.7%), menthyl acetate (19.2%) in <i>Mentha x piperita</i>, terpinen-4-ol (27.1%), (E)-sabinene hydrate (12.1%), <i>γ</i>-terpinene (10.0%) in <i>Origanum majorana</i>, <i>α</i>-thujone (19.5%), camphor (19.0%), viridiflorol (13.5%) in <i>Salvia officinalis</i>, thymol (61.9%), <i>p</i>-cymene (10.0%), <i>γ</i>-terpinene (10.0%) in <i>Thymus vulgaris</i>. Based on the MIC and MBC values (0.09–0.78 mg/mL) and ratio MBC/MIC showed that EO from <i>T. vulgaris</i> (TO) had the strong inhibitory and bactericidal effect against multidrug-resistant <i>Staphylococcus aureus</i>. The bacterial cells were total killed by TO at 2MIC concentration after 6 h. The higher concentrations of other EOs were needed to achieve bactericidal effects. The strong bactericidal effect of TO against these bacteria indicates the possibility of topical use of TO but it requires research under clinical conditions.</p

Coexistence of Borrelia burgdorferi s. l. genospecies within Ixodes ricinus ticks from central and eastern Poland

The purpose of the study was to assess the prevalence and coinfection rates of Borrelia burgdorferisensu lato genotypes inIxodes ricinus(L.) ticks sampled from diverse localities in central and eastern regions of Poland. In years 2009-2011, questingnymphs and adults ofI. ricinuswere collected using a flagging method at 18 localities representing distinct ecosystem types:urban green areas, suburban forests and rural woodlands. Molecular detection of B. burgdorferis.l. genospecies was based onamplification of a flagene using nested PCR technique, subsequent PCR-RFLP analysis and bidirectional sequencing. It wasrevealed that 45 samples (2.1%) harboured two different B. burgdorferis.l. genospecies, whereas triple infections with variousspirochetes was found in 11 (0.5%) individuals. Generally, the highest average coinfection rates were evidenced in arachnidsgathered at rural woodlands, intermediate at suburban forests, while the lowest were recorded at urban green areas. Overall, sin-gle spirochete infections were noted in 16.3% (n = 352/2,153) ticks. Importantly, it is the first report evidencing the occurrenceof Borrelia miyamotoi(0.3%, n = 7/2153) in I. ricinuspopulations within central Poland. Circumstantial variability of B. burgdorferis.l. genospecies in the common tick individuals sampled at various habitat types in central and eastern Polandwas displayed. The coexistence of two or three different spirochete genospecies in single adult ticks, as well as the presence ofB. miyamotoiwere demonstrated. Therefore, further studies uncovering the co-circulation of the tested bacteria and other humanpathogens in I. ricinusticks are require

Influence of the tested cereal aphids on <i>gst23</i> gene expression in the seedlings of Ambrozja and Tasty Sweet maize cultivars.

<p>Values signify the mean <i>n</i>-fold changes in the <i>gst23</i> transcript abundance in the aphid-stressed <i>Z. mays</i> plants in comparison with the non-infested group of seedlings. Error bars represent the standard deviation (± SD). For each maize-aphid treatment, three independent biological replicates were accomplished. The obtained gene expression data were normalized to the <i>gapdh</i> gene. The different letters above the SD bars designate significant differences among compared plants at P≤0.05 based on the Tukey's test. I-10, I-20, I-40 and I-60 are the levels of aphid infestation (10, 20, 40 and 60 insects per plant, accordingly).</p

Expression Profiling of Selected Glutathione Transferase Genes in <i>Zea mays</i> (L.) Seedlings Infested with Cereal Aphids

<div><p>The purpose of this report was to evaluate the expression patterns of selected glutathione transferase genes (<i>gst1</i>, <i>gst18</i>, <i>gst23</i> and <i>gst24</i>) in the tissues of two maize (<i>Zea mays</i> L.) varieties (relatively resistant Ambrozja and susceptible Tasty Sweet) that were colonized with oligophagous bird cherry-oat aphid (<i>Rhopalosiphum padi</i> L.) or monophagous grain aphid (<i>Sitobion avenae</i> L.). Simultaneously, insect-triggered generation of superoxide anion radicals (O₂^•−) in infested <i>Z. mays</i> plants was monitored. Quantified parameters were measured at 1, 2, 4, 8, 24, 48 and 72 h post-initial aphid infestation (hpi) in relation to the non-infested control seedlings. Significant increases in <i>gst</i> transcript amounts were recorded in aphid-stressed plants in comparison to the control seedlings. Maximal enhancement in the expression of the <i>gst</i> genes in aphid-attacked maize plants was found at 8 hpi (<i>gst23</i>) or 24 hpi (<i>gst1</i>, <i>gst18</i> and <i>gst24</i>) compared to the control. Investigated <i>Z. mays</i> cultivars formed excessive superoxide anion radicals in response to insect treatments, and the highest overproduction of O₂^•− was noted 4 or 8 h after infestation, depending on the aphid treatment and maize genotype. Importantly, the Ambrozja variety could be characterized as having more profound increments in the levels of <i>gst</i> transcript abundance and O₂^•− generation in comparison with the Tasty Sweet genotype.</p></div