A role for lipid-mediated signaling in plant gravitropism.

Gravitropism is a universal plant response. It is initiated by the sensing of the primary signal (mass or pressure), which is then converted into chemical signals that are transduced and propagated in a precise spatial and temporal fashion, resulting in a differential growth response. Our thesis is that membrane lipids and lipid-mediated signaling pathways play critical roles in the initial signaling and in the establishment of polarity. In this review, we highlight results from recent literature and discuss the major questions that remain unanswered.

MGMT CpG island is invariably methylated in adult astrocytic and oligodendroglial tumors with IDH1 or IDH2 mutations.

We have previously identified a region containing 16 CpGs within the MGMT CpG islands which is critical for the transcriptional control of MGMT (Malley, Acta Neuropathol 2011). To investigate the patterns and incidence of MGMT methylation in astrocytic and oligodendroglial tumors, we quantitatively assessed methylation at these 16 CpGs using bisulfite modification followed by pyrosequencing of 362 gliomas not treated with temozolomide, and correlated the findings with previously identified patterns of genetic abnormalities, patients' age and survival. The MGMT gene was considered to be methylated when the mean methylation of the 16 CpGs was 10% or higher. This cut-off value distinguished diffuse astrocytomas with high and low MGMT expression. Within each tumor type, the patterns of methylation were highly variable and also highly heterogeneous across the 16 CpGs. A high incidence of MGMT methylation was observed in all subtypes of gliomas included in this study. Among a subset of 97 tumors where conventional methylation-specific PCR (MSP) was also applied, methylation was detected by both methods in 54 tumors, while the pyrosequencing results identified a further 17 tumors. No additional cases were found using MSP alone, indicating that pyrosequencing is a robust method for methylation analysis. All tumors with IDH1/IDH2 mutations except two had MGMT methylation, while there were many tumors with MGMT methylation, particularly primary glioblastomas, which had no mutations of IDH1/2. We suggest that MGMT methylation may be one of the earliest events in the development of astrocytic and oligodendroglial tumors.

The effects of transcutaneous electrical nerve stimulation on post-cesarean pain.

The purpose of this study was to examine the effect of continuous transcutaneous electrical nerve stimulation (TENS) near the incision site on post-cesarean pain and on analgesic intake during the early postoperative period. This investigation utilised a 2-group (TENS-treated and placebo TENS-treated), single-blind experimental design. Eighteen multiparous women, each having undergone an elective cesarean delivery, participated in the study. Nine patients received TENS and nine placebo stimulation. The treatment was continuous through to the third day following the day of surgery. The McGill Pain Questionnaire was used to estimate the three most frequent types of post-cesarean-associated pain, and records of the patients' analgesic intake were obtained from hospital charts. The results suggest that TENS was significantly more effective than placebo TENS in reducing cutaneous, movement-associated incisional pain. However, pain resulting from internal structures, i.e., deep pain, afterbirth pain (due to uterine contractions), and the somatic pain associated with decreased peristalsis (gas pains) were not amenable to TENS. No significant differences in analgesic intake were observed. The possible reasons for these findings are discussed.

The response of the poplar transcriptome to wounding and subsequent infection by a viral pathogen.

• The Populus-Poplar Mosaic Virus (PopMV) pathosystem is the best characterized of all forest tree-virus interactions. The details of the host response to this virus are completely unknown. • The transcript abundance for approximately 10 000 Populus genes was simultaneously interrogated using spotted cDNA microarrays. Relative transcript abundance was compared for RNA extracted from Populus leaves that were untreated, mock-inoculated leaves that were wounded by leaf abrasion and inoculated leaves that were abraded and then infected by virus. • Statistical analysis of the microarray data identified suites of genes that exhibited increased or decreased transcript abundance in response to wounding, systemic PopMV infection or both together. Genes implicated in programmed cell death, and cell wall reinforcement were a major feature of the wound response, whereas genes encoding metallothionein-like proteins, and proteins implicated in cell wall remodelling were a major feature of the PopMV response. • The identification of wound- and PopMV-regulated genes opens the door for future studies aimed at testing specific hypotheses related to the mechanisms used by forest trees to contend with stress.

Video presentation of the second stage of a two-stage repair for proximal hypospadias: a safe and reproducible technique.

OBJECTIVE: The aims of proximal hypospadias repair are good cosmetic outcomes with low rates of complication, with a low number of operative exposures, before the age of genital difference realisation. Neo-urethral fistula and stenosis are well recognised complications; with international rates of 3.8-16% and 1.3-15.6% respectively. We present the key steps of the second of a two staged repair in video format. METHOD: Video recording of the procedure performed on an 18-month-old with mid-penile hypospadias is presented. The steps are described; the importance of tension free tubularisation, layered urethral closure, suture technique, vascularised prepucal graft technique, optimal glanuloplasty, and penile shaft skin repair are highlighted. RESULT: The child was brought back to the day ward for catheter removal at 7 days; follow-up in clinic showed good postoperative appearance. This technique has been performed on 31 boys with a fistula rate and stenosis rate favourable to the literature. CONCLUSION: We demonstrate a two-stage technique by video format for proximal hypospadias which is reproducible and gives results comparable to the literature.

Increasing Phosphatidylinositol (4,5)-Bisphosphate Biosynthesis Affects Basal Signaling and Chloroplast Metabolism in Arabidopsis thaliana.

One challenge in studying the second messenger inositol(1,4,5)-trisphosphate (InsP3) is that it is present in very low amounts and increases only transiently in response to stimuli. To identify events downstream of InsP3, we generated transgenic plants constitutively expressing the high specific activity, human phosphatidylinositol 4-phosphate 5-kinase Iα (HsPIPKIα). PIP5K is the enzyme that synthesizes phosphatidylinositol (4,5)-bisphosphate (PtdIns(4,5)P2); this reaction is flux limiting in InsP3 biosynthesis in plants. Plasma membranes from transgenic Arabidopsis expressing HsPIPKIα had 2-3 fold higher PIP5K specific activity, and basal InsP3 levels in seedlings and leaves were >2-fold higher than wild type. Although there was no significant difference in photosynthetic electron transport, HsPIPKIα plants had significantly higher starch (2-4 fold) and 20% higher anthocyanin compared to controls. Starch content was higher both during the day and at the end of dark period. In addition, transcripts of genes involved in starch metabolism such as SEX1 (glucan water dikinase) and SEX4 (phosphoglucan phosphatase), DBE (debranching enzyme), MEX1 (maltose transporter), APL3 (ADP-glucose pyrophosphorylase) and glucose-6-phosphate transporter (Glc6PT) were up-regulated in the HsPIPKIα plants. Our results reveal that increasing the phosphoinositide (PI) pathway affects chloroplast carbon metabolism and suggest that InsP3 is one component of an inter-organelle signaling network regulating chloroplast metabolism.