MS23, a master basic helix-loop-helix factor, regulates the specification and development of the tapetum in maize.

Successful male gametogenesis involves orchestration of sequential gene regulation for somatic differentiation in pre-meiotic anthers. We report here the cloning of Male Sterile23 (Ms23), encoding an anther-specific predicted basic helix-loop-helix (bHLH) transcription factor required for tapetal differentiation; transcripts localize initially to the precursor secondary parietal cells then predominantly to daughter tapetal cells. In knockout ms23-ref mutant anthers, five instead of the normal four wall layers are observed. Microarray transcript profiling demonstrates a more severe developmental disruption in ms23-ref than in ms32 anthers, which possess a different bHLH defect. RNA-seq and proteomics data together with yeast two-hybrid assays suggest that MS23 along with MS32, bHLH122 and bHLH51 act sequentially as either homo- or heterodimers to choreograph tapetal development. Among them, MS23 is the earliest-acting factor, upstream of bHLH51 and bHLH122, controlling tapetal specification and maturation. By contrast, MS32 is constitutive and independently regulated and is required later than MS23 in tapetal differentiation.

Smartphone learning as an adjunct to vascular teaching - a pilot project.

BACKGROUND: M-learning is education using personal mobile electronic devices. Given the prevalence of these in society and amongst healthcare professionals, we aimed to assess their use and feasibility in improving the educational programme of a single vascular institution. METHODS: A weekly vascular departmental teaching programme was initiated with registrars giving 30-min presentations on a defined book chapter. Two multiple-choice questions (MCQ) per session were devised by a supervising consultant utilising the smartphone response system application, Polltogo. A separate investigator disseminated one pre-teaching and one post-teaching MCQ to the attending trainees via a WhatsApp group. Instant feedback of the correct answer was provided by the application. Participants' satisfaction was judged through a survey after 13 sessions. RESULTS: 11 junior doctors of varying seniority participated in the trial. The median number of session attendees was 5. 129 MCQ responses were received. The mobile engagement score (number of answers received divided by total possible answers) was 97.7%. The average correct score for pre-teaching MCQs was 39.4% and post-teaching MCQs 73.0% (p < 0.001). Satisfaction with the concept was high; 80% of responders agreed that it was a useful adjunct to the teaching programme whilst 90% found the system highly user-friendly. CONCLUSIONS: Smartphones can be utilised effectively and with high user satisfaction in assessing knowledge transfer throughout a departmental education programme. Trainees' responses to MCQs significantly improved after 30-min teaching sessions. This concept of m-learning could be developed further to assist with postgraduate examination revision or Deanery teaching programmes in larger cohorts.

Sequencing, mapping, and analysis of 27,455 maize full-length cDNAs.

Full-length cDNA (FLcDNA) sequencing establishes the precise primary structure of individual gene transcripts. From two libraries representing 27 B73 tissues and abiotic stress treatments, 27,455 high-quality FLcDNAs were sequenced. The average transcript length was 1.44 kb including 218 bases and 321 bases of 5' and 3' UTR, respectively, with 8.6% of the FLcDNAs encoding predicted proteins of fewer than 100 amino acids. Approximately 94% of the FLcDNAs were stringently mapped to the maize genome. Although nearly two-thirds of this genome is composed of transposable elements (TEs), only 5.6% of the FLcDNAs contained TE sequences in coding or UTR regions. Approximately 7.2% of the FLcDNAs are putative transcription factors, suggesting that rare transcripts are well-enriched in our FLcDNA set. Protein similarity searching identified 1,737 maize transcripts not present in rice, sorghum, Arabidopsis, or poplar annotated genes. A strict FLcDNA assembly generated 24,467 non-redundant sequences, of which 88% have non-maize protein matches. The FLcDNAs were also assembled with 41,759 FLcDNAs in GenBank from other projects, where semi-strict parameters were used to identify 13,368 potentially unique non-redundant sequences from this project. The libraries, ESTs, and FLcDNA sequences produced from this project are publicly available. The annotated EST and FLcDNA assemblies are available through the maize FLcDNA web resource (www.maizecdna.org).

Transcriptomic, proteomic and metabolomic analysis of UV-B signaling in maize.

BACKGROUND: Under normal solar fluence, UV-B damages macromolecules, but it also elicits physiological acclimation and developmental changes in plants. Excess UV-B decreases crop yield. Using a treatment twice solar fluence, we focus on discovering signals produced in UV-B-irradiated maize leaves that translate to systemic changes in shielded leaves and immature ears. RESULTS: Using transcriptome and proteomic profiling, we tracked the kinetics of transcript and protein alterations in exposed and shielded organs over 6 h. In parallel, metabolic profiling identified candidate signaling molecules based on rapid increase in irradiated leaves and increased levels in shielded organs; pathways associated with the synthesis, sequestration, or degradation of some of these potential signal molecules were UV-B-responsive. Exposure of just the top leaf substantially alters the transcriptomes of both irradiated and shielded organs, with greater changes as additional leaves are irradiated. Some phenylpropanoid pathway genes are expressed only in irradiated leaves, reflected in accumulation of pathway sunscreen molecules. Most protein changes detected occur quickly: approximately 92% of the proteins in leaves and 73% in immature ears changed after 4 h UV-B were altered by a 1 h UV-B treatment. CONCLUSIONS: There were significant transcriptome, proteomic, and metabolomic changes under all conditions studied in both shielded and irradiated organs. A dramatic decrease in transcript diversity in irradiated and shielded leaves occurs between 0 h and 1 h, demonstrating the susceptibility of plants to short term UV-B spikes as during ozone depletion. Immature maize ears are highly responsive to canopy leaf exposure to UV-B.

Compartment syndrome: a rare complication following laparoscopic colorectal surgery.

We present a 71-year-old man who developed left calf pain after an elective laparoscopic assisted anterior resection. A clinical picture with a raised creatine kinase and negative Doppler ultrasound was suggestive of compartment syndrome. Successful surgical management was performed with two incisional fasciotomies to release all four compartments of the left leg. The patient recovered well postoperatively. The lateral incision was closed primarily while the medial incision required vacuum-assisted closure dressings and healed by secondary intention. Neither wound required skin grafts. The patient recovered well but had an extended hospital stay due to extensive physiotherapy requirements and mild foot drop. This report is intended as a guide for clinicians when considering differentials in calf pain following surgery and to keep in mind the small risk of developing compartment syndrome after pelvic surgery.

Reducing the risk of venous thromboembolism following superficial endovenous treatment: A UK and Republic of Ireland consensus study.

OBJECTIVES: Venous thromboembolism is a potentially fatal complication of superficial endovenous treatment. Proper risk assessment and thromboprophylaxis could mitigate this hazard; however, there are currently no evidence-based or consensus guidelines. This study surveyed UK and Republic of Ireland vascular consultants to determine areas of consensus. METHODS: A 32-item survey was sent to vascular consultants via the Vascular and Endovascular Research Network (phase 1). These results generated 10 consensus statements which were redistributed (phase 2). 'Good' and 'very good' consensus were defined as endorsement/rejection of statements by >67% and >85% of respondents, respectively. RESULTS: Forty-two consultants completed phase 1. This generated seven statements regarding risk factors mandating peri-procedural pharmacoprophylaxis and three statements regarding specific pharmacoprophylaxis regimes. Forty-seven consultants completed phase 2. Regarding venous thromboembolism risk factors mandating pharmacoprophylaxis, 'good' and 'very good' consensus was achieved for 5/7 and 2/7 statements, respectively. Regarding specific regimens, 'very good' consensus was achieved for 3/3 statements. CONCLUSIONS: The main findings from this study were that there was 'good' or 'very good' consensus that patients with any of the seven surveyed risk factors should be given pharmacoprophylaxis with low-molecular-weight heparin. High-risk patients should receive one to two weeks of pharmacoprophylaxis rather than a single dose.

Distinctive transcriptome responses to adverse environmental conditions in Zea mays L.

SUMMARY: Maize seedling transcriptome responses to six abiotic perturbations (heat, cold, darkness, desiccation, salt, ultraviolet-B) were analysed. Approximately 7800 transcripts were expressed in one or more treatments compared with light-grown seedlings plus juvenile leaves from field-grown plants. Approximately 5200 transcripts were expressed in one or more treatments and absent in light-grown seedlings. Approximately 2000 transcripts were unique to one treatment. Salt and heat elicited the largest number of transcript changes; however, salt resulted in mostly a decreased abundance of transcripts, whereas heat shock resulted in mostly an increased abundance of transcripts. A total of 384 transcripts were common to all stress treatments and not expressed in light-grown seedlings; 146 transcripts were present in light-grown seedlings and absent from all stress treatments. A complex pattern of overlapping transcripts between treatments was found, and a significant pattern of congruence in the direction of transcript change between pairs of treatments was uncovered. From the analysis, it appears that the scope of gene expression changes is determined by the challenge, indicating specificity in perception and response. Nonetheless, transcripts regulated by multiple responses are generally affected in the same manner, indicating common or converging regulatory networks. The data are available for additional analysis through a searchable database.

Endovascular Aneurysm Sealing for Management of Aortic Occlusive Disease.

INTRODUCTION: Endovascular management of aortic occlusive disease is an alternative to open surgery. This case describes the use of a Nellix graft to treat infrarenal aortic stenosis, outwith the graft indication for use. CASE REPORT: A 71 year old man with multiple comorbidities, presented with bilateral buttock claudication. A computed tomography angiogram (CTA) showed significant infrarenal aortic stenosis. Under local anaesthetic, using a percutaneous approach, Nellix grafts were inserted. The patient was discharged within 24 hours. His claudication improved significantly. A 6 month follow-up CT showed stent patency. CONCLUSION: Although further research is necessary, this case suggests that Nellix is safe and effective for primary stenting of the stenotic infrarenal aorta.

A 5-Year Follow-up Study to Assess Clinical Outcomes of Patients with Diabetes Undergoing Lower Limb Angiography for Significant Peripheral Artery Disease.

INTRODUCTION: The optimal management for patients with diabetes and peripheral vascular disease-intermittent claudication or critical limb ischemia (CLI)-remains undetermined. METHODS: In a single-center retrospective analysis, we compared 1- and 5-year amputation-free survival rates in patients undergoing angiography subsequently treated with medical therapy or revascularization. RESULTS: 78 patients were included, 56 with CLI (mean age 77 years); 22 with claudication (mean age 75 years). Of the CLI cohort, 30 patients were medically treated. Their 1-year amputation-free survival rate was similar to those treated with revascularization (46.7% versus 50.0%, respectively). 8 patients in the claudicant cohort were treated conservatively. The 1-year amputation-free survival rate was 75.0% for conservative treatment versus 78.6% in those revascularized. Within the CLI cohort, in those conservatively treated 20% underwent major, and 16.7% minor amputations, compared to 15.4% and 23.1% in those revascularized. At 5 years in the claudicant cohort, the amputation-free survival rate was 37.5% with medical treatment, versus 71.4% for those treated with revascularization. For CLI, the 5-year amputation-free survival rate was 10% for conservative treatment, versus 26.9% for revascularization. CONCLUSION: We found similar rates of amputation at 1 year for patients treated medically or revascularized. However, at 5 years, the amputation-free survival rate was markedly higher in revascularized patients compared to those medically managed. Our study highlights the potential role of predicting life expectancy when considering treatment, with the option of surgical treatment offered to those in whom survival is predicted to be longer than 5 years. However, larger studies with matched cohorts are now needed to confirm these findings.

Transcriptomes and proteomes define gene expression progression in pre-meiotic maize anthers.

Plants lack a germ line; consequently, during reproduction adult somatic cells within flowers must switch from mitotic proliferation to meiosis. In maize (Zea mays L.) anthers, hypoxic conditions in the developing tassel trigger pre-meiotic competence in the column of pluripotent progenitor cells in the center of anther lobes, and within 24 hr these newly specified germinal cells have patterned their surrounding neighbors to differentiate as the first somatic niche cells. Transcriptomes were analyzed by microarray hybridization in carefully staged whole anthers during initial specification events, after the separation of germinal and somatic lineages, during the subsequent rapid mitotic proliferation phase, and during final pre-meiotic germinal and somatic cell differentiation. Maize anthers exhibit a highly complex transcriptome constituting nearly three-quarters of annotated maize genes, and expression patterns are dynamic. Laser microdissection was applied to begin assigning transcripts to tissue and cell types and for comparison to transcriptomes of mutants defective in cell fate specification. Whole anther proteomes were analyzed at three developmental stages by mass spectrometric peptide sequencing using size-fractionated proteins to evaluate the timing of protein accumulation relative to transcript abundance. New insights include early and sustained expression of meiosis-associated genes (77.5% of well-annotated meiosis genes are constitutively active in 0.15 mm anthers), an extremely large change in transcript abundances and types a few days before meiosis (including a class of 1340 transcripts absent specifically at 0.4 mm), and the relative disparity between transcript abundance and protein abundance at any one developmental stage (based on 1303 protein-to-transcript comparisons).

Use of an Amplatzer vascular plug II for aortic sac occlusion after failed surgical ligation.

PURPOSE: To present a case of aortic sac occlusion using an Amplatzer vascular plug II (AVP). CASE REPORT: A patient with sigmoid malignancy and an infrarenal aortic aneurysm ultimately required an axillobifemoral graft for acute limb ischemia. The sac was ligated at subsequent laparotomy. Persistent filling of the sac was seen post surgery, and the sac was successfully occluded with placement of an AVP in the neck of the sac in conjunction with coil embolization of lumbar arteries. Sac occlusion was confirmed at follow-up CT. CONCLUSION: The AVP was successfully used to occlude an aortic sac after failed surgical ligation, another novel indication for this versatile embolic device.

Transcriptomic, proteomic and metabolomic analysis of maize responses to UV-B: comparison of greenhouse and field growth conditions.

UV-B radiation from normal solar fluence elicits physiological and developmental changes in plants under fluctuating environmental conditions. Most UV photobiology studies in plants utilize controlled greenhouse and growth chamber environments in which few conditions vary except the brief presence of UV-B radiation. Our purpose was to compare responses to UV-B in irradiated and shielded maize organs in field (natural solar plus 2x solar supplementation for defined periods) and greenhouse (2x solar supplementation only) conditions during a 4 hour exposure. Three parameters were assessed--transcripts, proteins, and metabolites--to determine the degree of overlap in maize responses in field and greenhouse conditions. We assessed irradiated leaves, and both shielded leaves and immature ears. After comparing transcriptome, proteome and metabolome profiles, we find there are more differences than similarities between field and greenhouse responses.

UV-B signaling in maize: transcriptomic and metabolomic studies at different irradiation times.

Plants have evolved adaptations to environmental factors, including UV-B present in solar radiation. Deployment of specific adaptive phenotypes to avoid or repair UV-B damage requires physiological and developmental acclimation to variable UV-B fluence. To gain a better understanding of the events in UV-B acclimation, we have analyzed a 5min to 6h time course of transcriptome and metabolome responses in irradiated and shielded leaves and in immature maize ears to unravel the systemic physiological and developmental responses in exposed and shielded organs. Within 10 min of UV-B exposure, transcripts are changed not only in irradiated leaves, but also in shielded tissues. The number of UV-B-regulated transcripts rapidly increases with exposure length. Interestingly, after 10 min of exposure, the overlap in transcriptome changes in irradiated and shielded organs is significant; while, after 6h of UV-B, most transcripts are specific for each tissue under study. We suggest that early events in all tissues may be elicited by common signaling pathways, while at longer exposure times responses become more organ-specific. Our working hypothesis is that mobile signaling molecules are generated in irradiated organs to elicit the initial responses. We found several metabolites that rapidly change after different treatments during the timecourse; myoinositol is one candidate metabolite based on its rapid modulation in all organs. There is also support from RNA profiling: after 1h UV-B, transcripts for myoinositol-1-phosphate synthase are decreased in both irradiated and shielded leaves suggesting downregulation of biogenesis.

Rapid Maize Leaf and Immature Ear Responses to UV-B Radiation.

Because of their sessile lifestyle, plants have evolved adaptations to environmental factors, including UV-B present in solar radiation. To gain a better understanding of the initial events in UV-B acclimation, we have analyzed a 10 min to 1 h time course of transcriptome responses in irradiated and shielded leaves, and immature maize ears to unravel the systemic physiological and developmental responses in exposed and shielded organs. After 10 min of UV-B exposure, 262 transcripts are changed by at least two-fold in irradiated leaves, and this number doubles after 1 h. Indicative of the rapid modulation of transcription, 130 transcripts are only changed after 10 min. This is true not only in irradiated leaves, but also in shielded tissues. After 10 min of exposure, the overlap in transcriptome changes in irradiated and shielded organs is significant; however, after 30 min of UV-B, there are only two transcripts showing similar UV-B regulation between the three organs; 35 are similarly regulated in both IL and SL. Therefore, at longer irradiation times, there is more specificity of responses, and these are organ-specific. We suggest that early signaling in different tissues may be elicited by common signaling pathways, while at longer exposure times responses become more specific. To identify metabolites as possible signaling molecules, we looked for compounds that increased within 5-90 min in both irradiated and shielded leaves, to explain the kinetics of profound transcript changes within 1 h. We found that myoinositol is one such candidate metabolite; and we also demonstrate that if 0.1 mM myoinositol is applied to leaves of greenhouse maize, some metabolites that are changed by UV-B are also changed similarly by the chemical treatment. Therefore, this metabolite can partially mimic UV irradiation.

Transcriptome profiling of maize anthers using genetic ablation to analyze pre-meiotic and tapetal cell types.

Oligonucleotide arrays were used to profile gene expression in dissected maize anthers at four stages: after-anther initiation, at the rapid mitotic proliferation stage, pre-meiosis, and meiotic prophase I. Nearly 9200 sense and antisense transcripts were detected, with the most diverse transcriptome present at the pre-meiotic stage. Three male-sterile mutants lacking a range of normal cell types resulting from a temporal progression of anther failure were compared with fertile siblings at equivalent stages by transcription profiles. The msca1 mutant has the earliest visible phenotype, develops none of the normal anther cell types and exhibits the largest deviation from fertile siblings. The mac1 mutant has an excess of archesporial derivative cells and lacks a tapetum and middle layer, resulting in moderate transcriptional deviations. The ms23 mutant lacks a differentiated tapetum and shows the fewest differences from fertile anthers. By combining the data sets from the comparisons between individual sterile and fertile anthers, candidate genes predicted to play important roles during maize anther development were assigned to stages and to likely cell types. Comparative analyses with a data set of anther-specific genes from rice highlight remarkable quantitative similarities in gene expression between these two grasses.

Comparative profiling of the sense and antisense transcriptome of maize lines.

BACKGROUND: There are thousands of maize lines with distinctive normal as well as mutant phenotypes. To determine the validity of comparisons among mutants in different lines, we first address the question of how similar the transcriptomes are in three standard lines at four developmental stages. RESULTS: Four tissues (leaves, 1 mm anthers, 1.5 mm anthers, pollen) from one hybrid and one inbred maize line were hybridized with the W23 inbred on Agilent oligonucleotide microarrays with 21,000 elements. Tissue-specific gene expression patterns were documented, with leaves having the most tissue-specific transcripts. Haploid pollen expresses about half as many genes as the other samples. High overlap of gene expression was found between leaves and anthers. Anther and pollen transcript expression showed high conservation among the three lines while leaves had more divergence. Antisense transcripts represented about 6 to 14 percent of total transcriptome by tissue type but were similar across lines. Gene Ontology (GO) annotations were assigned and tabulated. Enrichment in GO terms related to cell-cycle functions was found for the identified antisense transcripts. Microarray results were validated via quantitative real-time PCR and by hybridization to a second oligonucleotide microarray platform. CONCLUSION: Despite high polymorphisms and structural differences among maize inbred lines, the transcriptomes of the three lines displayed remarkable similarities, especially in both reproductive samples (anther and pollen). We also identified potential stage markers for maize anther development. A large number of antisense transcripts were detected and implicated in important biological functions given the enrichment of particular GO classes.

Progress in maize gene discovery: a project update.

The Maize Gene Discovery Project (MGDP) is a 5-year NSF-funded plant genome initiative that began in 1998. The MGDP collaboration involves researchers at six universities from diverse disciplines with the common goal of discovering new maize genes and developing tools for the phenotypic characterization of maize mutants. The project utilizes several approaches: EST sequencing, cDNA microarray production, and the discovery of gene function and genomic sequence through the use of a recombinant Mu1 transposon ( RescueMu). Current achievements of the MGDP (NSF 98-72657) include the sequencing of over 120,000 maize ESTs from diverse cDNA libraries, and over 70,000 RescueMu flanking sequences, as well as the cataloguing of mutant seed and cob phenotypes of 23,000 maize ears, 6,200 families of maize seedlings, and 4,000 families of adult maize plants carrying MuDR/Mu and RescueMu insertion alleles. A consolidation of over 24,000 unique sequences from 19 libraries has been made into the first two of the planned set of four "Unigene" microarray slides. In addition, slides for four EST libraries have been produced. These microarray slides, EST clones, library plates of immortalized RescueMu bacterial cultures, and seed are all available online (http://www.zmdb.iastate.edu). The ZmDB website posts periodic assemblies of all maize EST and genomic sequences available from GenBank. ZmDB is also a portal for sequence analysis software designed to aid in gene discovery: MuSeqBox, GeneSeqer, and SplicePredictor. In addition, ZmDB contains links to other plant and genetics websites.