Hydrogen Peroxide: Its Role in Plant Biology and Crosstalk with Signalling Networks.

Hydrogen peroxide (H2O2) is steadily gaining more attention in the field of molecular biology research. It is a major REDOX (reduction⁻oxidation reaction) metabolite and at high concentrations induces oxidative damage to biomolecules, which can culminate in cell death. However, at concentrations in the low nanomolar range, H2O2 acts as a signalling molecule and in many aspects, resembles phytohormones. Though its signalling network in plants is much less well characterized than are those of its counterparts in yeast or mammals, accumulating evidence indicates that the role of H2O2-mediated signalling in plant cells is possibly even more indispensable. In this review, we summarize hydrogen peroxide metabolism in plants, the sources and sinks of this compound and its transport via peroxiporins. We outline H2O2 perception, its direct and indirect effects and known targets in the transcriptional machinery. We focus on the role of H2O2 in plant growth and development and discuss the crosstalk between it and phytohormones. In addition to a literature review, we performed a meta-analysis of available transcriptomics data which provided further evidence for crosstalk between H2O2 and light, nutrient signalling, temperature stress, drought stress and hormonal pathways.

Role of the proteome in phytohormonal signaling.

Phytohormones are orchestrators of plant growth and development. A lot of time and effort has been invested in attempting to comprehend their complex signaling pathways but despite success in elucidating some key components, molecular mechanisms in the transduction pathways are far from being resolved. The last decade has seen a boom in the analysis of phytohormone-responsive proteins. Abscisic acid, auxin, brassinosteroids, cytokinin, ethylene, gibberellins, nitric oxide, oxylipins, strigolactones, salicylic acid--all have been analyzed to various degrees. For this review, we collected data from proteome-wide analyses resulting in a list of over 2000 annotated proteins from Arabidopsis proteomics and nearly 500 manually filtered protein families merged from all the data available from different species. We present the currently accepted model of phytohormone signaling, highlight the contributions made by proteomic-based research and describe the key nodes in phytohormone signaling networks, as revealed by proteome analysis. These include ubiquitination and proteasome mediated degradation, calcium ion signaling, redox homeostasis, and phosphoproteome dynamics. Finally, we discuss potential pitfalls and future perspectives in the field. This article is part of a Special Issue entitled: Plant Proteomics--a bridge between fundamental processes and crop production, edited by Dr. Hans-Peter Mock.

Prevalence and impact of restless legs syndrome in pregnancy.

BACKGROUND: Restless legs syndrome (RLS) is a frequent neurological disorder which predominantly affects women. Pregnancy is one of the most common conditions leading to secondary RLS. Severe symptoms of RLS may lead to complications of pregnancy and/or labor. The aim of this study was to determine the prevalence and characteristics of RLS in pregnant women. METHODS: Women in the third trimester of gravidity filled out a simple questionnaire based on the official diagnostic criteria for RLS. Positive responders were interviewed in order to further characterize their symptoms. Afterwards information on changes in frequency and/or intensity of the symptoms after delivery was obtained by a telephone follow-up. All data were statistically analysed. RESULTS: A total of 300 questionnaires were completed. All 94 RLS-positives met the four diagnostic criteria (31.33%). There was no difference in age, body mass index, or the number of previous pregnancies between RLS-positives and RLS-negatives, but weight gain during pregnancy was significantly higher in RLS-positives. More than 30% of positives had clinically significant symptoms, and 50% reported sleep disturbances. Almost 75% of the cases of RLS were secondary, i.e., symptoms occurred only during pregnancy (with a peak in the third trimester). More complications of pregnancy or labor occurred in women with RLS, but this was only marginally significant. CONCLUSIONS: Our study confirmed the relatively high prevalence of RLS in pregnant women compared with the general population. Although almost three-fourths of the symptoms were only transient throughout pregnancy, the impact of the severe symptoms and sleep deprivation on the course of pregnancy and delivery was not negligible. Early detection and adequate treatment of severe RLS are necessary to prevent maternal discomfort and possible health risks. The questionnaire method is a simple, reliable diagnostic tool.

Emergency Uterine Artery Embolization Used for Managing Profuse Intra-Abdominal Bleeding and Uterine Rupture in a Patient with Advanced Cervical Cancer.

Advanced cervical cancer can lead to life-threatening vaginal bleeding. Emergency uterine artery embolization (UAE) has been successfully used in such cases to achieve hemostasis. Our case demonstrates the unusual emergency use of this procedure to cease heavy hemorrhage, which led to hematometra, uterine rupture and hemoperitoneum in a patient with a large tumor in the cervical region. Vaginal bleeding was minimal in this case. The emergency UAE controlled the bleeding, and the patient was scheduled for laparotomy soon after the procedure, where a supracervical hysterectomy with bilateral salpingo-oophorectomy and the removal of blood and blood clots was performed. Since the tumor primarily involved the parametria, a sample was taken for histopathology examination with the following result: squamocellular HPV-associated cervical carcinoma. The postoperative management of the patient consisted of combined chemotherapy and radiotherapy, with no complications related to the UAE. Four months after the procedure the patient is reasonably well. Urgent surgery was not the optimal decision because of the alteration of the pelvic anatomy by the tumor, and thus the UAE enabled us to manage this life-threatening condition quickly, allowing us to best prepare the patient for further therapeutic modalities.

Prenatal Diagnosis of Torcular Dural Sinus Malformation: A Case Study.

Torcular dural sinus malformations (tDSMs) are rare congenital defects representing a complex of vascular anomalies that have been grouped in one single unit. Although the current literature suggests a generally favourable prognosis for prenatally diagnosed tDSMs, there are still only limited data and published papers on the subject. Factors resulting in an adverse outcome of the fetuses and children have to be taken into consideration to determine precisely the nature of the consultation and management. A 33-year-old primipara at 21 weeks, 5 days of gestation was referred to our clinic with the suspicion of a central nervous system (CNS) malformation of the fetus, and the diagnosis of tDSM with thrombus was made. No factors contributing to an adverse outcome such as arterialization of the lesion, ventriculomegaly or neuroparenchymal damage were present. The pregnant woman was scheduled for regular sonographic and magnetic resonance imaging (MRI) controls. In the third trimester the lesion decreased in size, which is a key imaging marker for a favourable prognosis. The child was born in term, and the latest neurological examination at the age of six weeks is without pathological findings. This case study demonstrates a prenatally diagnosed tDSM with a favourable outcome with a regression in the size of the lesion during the prenatal period.

Fractionation Techniques to Increase Plant Proteome Coverage: Combining Separation in Parallel at the Protein and the Peptide Level.

Peptide spectral libraries enable targeted identification and quantitation of low-abundance proteins in a complex plant proteome. Here we describe parallel protein and peptide fractionation techniques to improve plant proteome coverage and facilitate construction of spectral libraries.

Proteomics offers insight to the mechanism behind Pisum sativum L. response to pea seed-borne mosaic virus (PSbMV).

Pea seed-borne mosaic virus (PSbMV) significantly reduces yields in a broad spectra of legumes. The eukaryotic translation initiation factor has been shown to confer resistance to this pathogen, thus implying that translation and proteome dynamics play a role in resistance. This study presents the results of a proteome-wide analysis of Pisum sativum L. response to PSbMV infection. LC-MS profiling of two contrasting pea cultivars, resistant (B99) and susceptible (Raman) to PSbMV infection, detected >2300 proteins, 116 of which responded to PSbMV ten and/or twenty days post-inoculation. These differentially abundant proteins are involved in number of processes that have previously been reported in the plant-pathogen response, including protein and amino acid metabolism, stress signaling, redox homeostasis, carbohydrate metabolism, and lipid metabolism. We complemented our proteome-wide analysis work with targeted analyses of free amino acids and selected small molecules, fatty acid profiling, and enzyme activity assays. Data from these additional experiments support our findings and validate the biological relevance of the observed proteome changes. We found surprising similarities in the resistant and susceptible cultivars, which implies that a seemingly unaffected plant, with no detectable levels of PSbMV, actively suppresses viral replication. BIOLOGICAL SIGNIFICANCE: Plant resistance to PSbMV is connected to translation initiation factors, yet the processes involved are still poorly understood at the proteome level. To the best of our knowledge, this is the first survey of the global proteomic response to PSbMV in plants. The combination of label-free LC-MS profiling and two contrasting cultivars (resistant and susceptible) provided highly sensitive snapshots of protein abundance in response to PSbMV infection. PSbMV is a member of the largest family of plant viruses and our results are in accordance with previously characterized potyvirus-responsive proteomes. Hence, the results of this study can further extend our knowledge about these pathogens. We also show that even though no viral replication is detected in the PSbMV-resistant cultivar B99, it is still significantly affected by PSbMV inoculation.

Restless legs syndrome in pregnancy is connected with iron deficiency.

OBJECTIVE: Almost one-third of pregnant women develop symptoms of restless legs syndrome (RLS), which could have a negative impact on quality of life and the course of pregnancy and/or labor. The aim of our study was to determine possible risk factors for developing RLS in pregnant women. METHODS: A total of 300 random women in the third trimester of gravidity filled out a simple questionnaire based on the official diagnostic criteria for RLS. Respondents positive for RLS were interviewed to further characterize their symptoms. The parameters of iron metabolism were examined based on blood samples. All data were statistically analyzed. RESULTS: We detected significantly lower hemoglobin levels with signs of hypochromic anemia typical of iron deficiency in RLS-positive respondents, although oral iron supplementation was significantly higher in this group. The overall severity of symptoms correlated inversely with hemoglobin level. CONCLUSION: According to our results, it appears that serum iron level disturbances play a crucial role in the pathophysiology of secondary RLS in pregnant women.