Interactions between iron and silicon in cucumber

Silicon (Si) and iron (Fe) are respectively the second and the fourth most abundant minerals in the earth’s crust. While the essentiality of Fe has been discovered in the middle of the 19th century, Si is still not fully accepted as an essential element for higher plants; however, Si is proved to alleviate multiple environmental stresses in plants. So far, Fe deficiency have mainly been studied and characterized in nutrient solution experiments devoid of Si, hence information on the interactions between these two minerals in plants is still limited. Here we investigated how Si ameliorates Fe deficiency in cucumber (model of Strategy 1 and Si-accumulating species), focusing on the mechanisms involved in Fe acquisition from the rhizosphere and utilization of root apoplastic Fe, as well as on Fe distribution towards young leaves in Fe-deficient cucumber plants. Application of Si increased the root apoplastic Fe pool, together with the enhanced expression of genes involved in reduction-based Fe uptake (FRO2, IRT1 and HA1). Moreover, in Fe deficient cucumber roots, Si influenced the genes involved in the carboxylate, shikimate and phenylpropanoid metabolism, thus resulted in enhanced accumulation of Fe chelating compounds (organic acids and phenolics) for improved Fe mobilization from the rhizosphere and reutilization of root apoplastic Fe (Pavlovic et al., 2013). Application of Si also facilitated mobility and xylem traslocation of Fe towards shoot, along with the accumulation of Fe-mobilizing compounds such as citrate in xylem sap, root and shoot tissues or cathechins in roots (Pavlovic et al., 2013; Bityutskii et al., 2014). Very recently, we demonstrated that Si enhanced remobilization of labelled 57Fe from old leaves and its retranslocation to the younger leaves is accompanied by Si-induced expression of genes encoding both NA biosynthesis (SAM and NAS) and YSL transporters responsible for symplastic Fe unloading in leaves and floem transport of Fe-NA complex. In conclusion, the alleviating effect of Si seems to be more indirect, by affecting activation of Fe deficiency-related genes responsible for enhanced root acquisition and tissue mobilization of Fe. This work not only provides new evidence for the beneficial role of Si in iron nutrition, but, in perspective, can be of practical importance in the development of new sustainable measures for controlling Fe chlorosis in calcareous soils, which in general are low in available Si

Bioavailability of Nutritional Resources From Cells Killed by Oxidation Supports Expansion of Survivors in Ustilago maydis Populations

After heavy exposure of Ustilago maydis cells to clastogens, a great increase in viability was observed if the treated cells were kept under starvation conditions. This restitution of viability is based on cell multiplication at the expense of the intracellular compounds freed from the damaged cells. Analysis of the effect of the leaked material on the growth of undamaged cells revealed opposing biological activity, indicating that U. maydis must possess cellular mechanisms involved not only in reabsorption of the released compounds from external environment but also in contending with their treatment-induced toxicity. From a screen for mutants defective in the restitution of viability, we identified four genes (adr1, did4, kel1, and tbp1) that contribute to the process. The mutants in did4, kel1, and tbp1 exhibited sensitivity to different genotoxic agents implying that the gene products are in some overlapping fashion involved in the protection of genome integrity. The genetic determinants identified by our analysis have already been known to play roles in growth regulation, protein turnover, cytoskeleton structure, and transcription. We discuss ecological and evolutionary implications of these results

Data_Sheet_1_Bioavailability of Nutritional Resources From Cells Killed by Oxidation Supports Expansion of Survivors in Ustilago maydis Populations.DOCX

<p>After heavy exposure of Ustilago maydis cells to clastogens, a great increase in viability was observed if the treated cells were kept under starvation conditions. This restitution of viability is based on cell multiplication at the expense of the intracellular compounds freed from the damaged cells. Analysis of the effect of the leaked material on the growth of undamaged cells revealed opposing biological activity, indicating that U. maydis must possess cellular mechanisms involved not only in reabsorption of the released compounds from external environment but also in contending with their treatment-induced toxicity. From a screen for mutants defective in the restitution of viability, we identified four genes (adr1, did4, kel1, and tbp1) that contribute to the process. The mutants in did4, kel1, and tbp1 exhibited sensitivity to different genotoxic agents implying that the gene products are in some overlapping fashion involved in the protection of genome integrity. The genetic determinants identified by our analysis have already been known to play roles in growth regulation, protein turnover, cytoskeleton structure, and transcription. We discuss ecological and evolutionary implications of these results.</p

Two metallothionein gene family members in buckwheat: Expression analysis in flooding stress using Real Time RT-PCR technology

Metalotioneini (MT) pripadaju velikoj grupi proteina male molekulske težine bogatih cisteinom, izražene sposobnosti za vezivanje jona metala, uključenih u procese održavanja homeostaze metalnih jona i detoksifikacije od teških metala. U radu je analizirana struktura dva transkripta gena za MT tipa 3 poreklom iz semena heljde u razviću. Razlike su nađene pre svega u okviru 3’- UTR sekvenci. Nakon analiza sekvenci urađena je analiza ekspresije tokom hipoksije korišćenjem tehnologije Real Tme RT-PCR.Metallothioneins (MTs) are an extensive and diverse family of small cysteine-rich proteins with metal-binding ability that are involved in metal homeostasis and detoxification. Two cDNA clones of the MT3 type, differing in 3’ UTRs, were isolated from the developing buckwheat seed cDNA library. Following sequence analyses, expression profiles during flooding stress were monitored by Real Time RT PCR technology

Silicon enhances leaf remobilization of iron in cucumber under limited iron conditions

Background and Aims Retranslocation of iron (Fe) from source tissues enhances plant tolerance to Fe deficiency. Previous work has shown that silicon (Si) can alleviate Fe deficiency by enhancing acquisition and root to shoot translocation of Fe. Here the role of Si in Fe mobilization in older leaves and the subsequent retranslocation of Fe to young leaves of cucumber (Cucumis sativus) plants growing under Fe-limiting conditions was investigated. Methods Iron (Fe-57 or naturally occurring isotopes) was measured in leaves at different positions on plants hydroponically growing with or without Si supply. In parallel, the concentration of the Fe chelator nicotianamine (NA) along with the expression of nicotianamine synthase (NAS) involved in its biosynthesis and the expression of yellow stripe-like (YSL) transcripts mediating Fe-NA transport were also determined. Key Results In plants not receiving Si, approximately half of the total Fe content remained in the oldest leaf. In contrast, Si-treated plants showed an almost even Fe distribution among leaves with four different developmental stages, thus providing evidence of enhanced Fe remobilization from source leaves. This Si-stimulated Fe export was paralleled by an increased NA accumulation and expression of the YSL1 transporter for phloem loading/unloading of the Fe-NA complex. Conclusions The results suggest that Si enhances remobilization of Fe from older to younger leaves by a more efficient NA-mediated Fe transport via the phloem. In addition, from this and previous work, a model is proposed of how Si acts to improve Fe homeostasis under Fe deficiency in cucumber.Free full text: [https://doi.org/10.1093/aob/mcw105]Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3608

THE IMPORTANCE OF DETERMINING THE UROMODULIN SERUM CONCENTRATION IN DIABETES MELLITUS TYPE 2 PATIENTS

Introduction: In the kidney, cells in the thick ascending limb of the loop of the Henle synthesized uromodulin (UMOD). This study aims to present the evaluation of the uromodulin serum concentration in diabetes mellitus type 2 (T2DM) patients in the early detection of kidney damage. Materials and methods: The study included 50 T2DM patients with a mean age of 60.75±11.23 years with estimated glomerular filtration rate (eGFR) 114.38±22.12 ml/min and a control group of 20 healthy persons. We measured serum concentration of haemoglobin, urea, creatinine, uromodulin (ELISA method), and cystatin C (nephelometry). We determined formulas: Cockcroft-Gault# (combination Cockcroft- Gault for patients with BMI< 30 kg/m2 and Cockcroft- GaultLBW for patients with BMI≥ 30 kg/m2), CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration equation), and simple Cystatin C. Results: T2DM patients had lower hemoglobin serum concentration as well as eGFR calculated by formulas: Cockcroft- Gault# and CKD-EPI. T2DM patients had significantly higher BMI and cystatin C compared to control group. T2DM patients had significantly lower serum uromodulin concentration (136.51±84.34 vs 220.50±92.39 ng/ml) than in controls. Significant positive correlation between uromodulin and Cockcroft- Gault# (r= 0.432, p= 0.000), CKD- EPI (r = 0.439; p = 0.000) formulas as well as simple cystatin C (r = 0.250, p = 0.02), but negative correlation with age (r = -0.476, p =0.000), BMI (r = -0.313, p = 0.002) and cystatin C serum concentration (r = -0.293, p = 0.015) were found. Conclusion: The role of serum uromodulin concentration is not still fortified. The results of this study showed that reduced uromodulin serum concentration indicated early kidney damage in T2DM patients

Prevalence of and contributing factors to overweight and obesity among the schoolchildren of Podgorica, Montenegro

Introduction/Objective. Childhood obesity is an emerging public health problem. The national prevalence of child overweight/obesity in Montenegro has increased by one third in the last decade. As the overwhelming majority of Montenegrin population is urban, investigation of obesity and correlates among urban children is of special public health interest. The aim of this study was to investigate the prevalence of and contributing factors to obesity among schoolchildren of Podgorica. Method. The sample included 1,134 schoolchildren (49.8% boys) aged 7–12 years, from 10 elementary schools in Podgorica. We measured children’s body mass, body height, and waist circumference to calculate body mass index (BMI) and waist-to-height ratio. The research instrument was a closed type of the original questionnaire. Nutritional status was assessed according to the criteria recommended by the American Centers for Disease Control and Prevention, World Health Organization and International Obesity Task Force. Results. Among the investigated children there were 21.2% and 6% overweight and obese children, respectively. Obesity was more frequent among boys (7.6%) compared to girls (4.4%). In a multiple regression, childhood obesity was positively related to the following: male gender, younger age, lower number of siblings, parental obesity, and low physical activity. Conclusion. One out of five urban Montenegrin schoolchildren is overweight/obese, with obesity being twice as frequent among boys compared to girls. A program against obesity among urban Montenegrin children should focus on the revealed contributing factors

Silicon alleviates iron deficiency in cucumber by promoting mobilization of iron in the root apoplast

Root responses to lack of iron (Fe) have mainly been studied in nutrient solution experiments devoid of silicon (Si). Here we investigated how Si ameliorates Fe deficiency in cucumber (Cucumis sativus) with focus on the storage and utilization of Fe in the root apoplast. A combined approach was performed including analyses of apoplastic Fe, reduction-based Fe acquisition and Fe-mobilizing compounds in roots along with the expression of related genes. Si-treated plants accumulated higher concentrations of root apoplastic Fe, which rapidly decreased when Fe was withheld from the nutrient solution. Under Fe-deficient conditions, Si also increased the accumulation of Fe-mobilizing compounds in roots. Si supply stimulated root activity of Fe acquisition at the early stage of Fe deficiency stress through regulation of gene expression levels of proteins involved in Fe acquisition. However, when the period of Fe deprivation was extended, these reactions further decreased as a consequence of Si-induced enhancement of the Fe status of the plants. This work provides new evidence for the beneficial role of Si in plant nutrition and clearly indicates that Si-mediated alleviation of Fe deficiency includes an increase of the apoplastic Fe pool in roots and an enhancement of Fe acquisition

Importance of pharmacogenetic markers in the methylenetetrahydrofolate reductase gene during methotrexate treatment in pediatric patients with acute lymphoblastic leukemia

Despite remarkable progress in survival of children with acute lymphoblastic leukemia (ALL) which has reached about 85%, early toxicity and relapse rate remain issues that need to to be resolved. Genetic variants are important factors influencing the metabolism of cytotoxic drugs in ALL treatment. Variants in genes coding for methotrexate (MTX)-metabolizing enzymes are under constant scientific interest due to their potential impact on drug toxicity and relapse rate. We investigated methylenetetrahydrofolate reductase (MTHFR) c.677C gt T and MTHFR c.1298A gt C variants as pharmacogenetic markers of MTX toxicity and predictors of relapse. The study enrolled 161 children with ALL, treated according to the current International Berlin-Frankfurt-Munster group (BFM) for diagnostics and treatment of leukemia and lymphoma protocols. Genotyping was performed using PCR-RFLP and allele-specific PCR assays. Our results revealed similar distributions of MTHFR c.677C gt T and MTHFR c.1298A gt C genotypes among 104 healthy individuals as compared to pediatric ALL patients. A lower incidence of early MTX toxicity was noted in the MTHFR c.677TT genotype (p=0.017), while MTHFR c.1298A gt C genotypes were not associated with MTX toxicity. Carriers of any MTHFR c.677C gt T and MTHFR c.1298A gt C genotypes did not experience decreased overall survival (OAS) or higher relapse rates. Genetic variants in the MTHFR gene are not involved in leukemogenesis in pediatric ALL. The presence of the MTHFR c.677TT genotype was recognized as a predictive factor for decreased MTX toxicity during the intensification phase of therapy. Neither MTHFR c.677C gt T nor MTHFR c.1298A gt C genotypes correlated with an increased number of toxic deaths or relapse rate. Our study emphasizes the importance of implementing pharmacogenetic markers in order to optimize pediatric ALL therapy