MicroRNA, sex determination and floral meristem determinacy in maize

Sex determination in maize inflorescences is determined by microRNA action

Molecular Phylogeny Implemented in an Introductory Plant Classification Course

Plant classification is one of the core components in undergraduate programs related to plant sciences. Traditionally plant classification courses primarily introduce morphology-based taxonomy because of practical needs in the field. However, the publication of new plant classification systems by Angiosperm Phylogeny Group (APG) using molecular phylogeny methods leads to the trends of using molecular evidence (DNA barcode) for plant identification. In our introductory plant classification course, we included a two-week module (lectures and labs) to introduce key concepts and fundamental skills in molecular phylogeny. Week 1 included concepts of evolutionary tree thinking, data mining in NCBI using BLAST search, and phylogenetic tree building. Week 2 introduced concepts of DNA sequencing and barcoding for plant identification. Student selected their own plants to sequence the DNA barcodes, which were then used in the final exam for practice and summative assessments. One challenge we are constantly dealing with is the increasing difficulty in finding diverse sequence using BLAST because of the fast-growing number of angiosperm genomes sequenced

Enid Booth Legend

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Genetic and Molecular Dissection of Arsenic Hyperaccumulation

We have constructed cDNA libraries from RNA isolated from arsenic treated gametophytes of the fern Pteris vittata. This library was made in a manner that allows each cDNA clone to be expressed in yeast. We have introduced this library into yeast cells, both wild type and arsensic sensitive mutants, and selected transformed yeast colonies with increased arsenic tolerance compared to the parental strains. From these screens we have identified putative homologs of the yeast ACR2 and ACR3 genes from Pteris vittata and, for the past year, have focused on characterizing the function of the ACR2 gene. In yeast, ACR2 is an arsenate reductase that is essential for arsenate tolerance. We refer to the Pteris vittata ACR2 gene as PvACR2. The deduced amino acid sequence of PvACR2 is highly similar to the yeast ACR2 and other related phosphatases

A systemic gene silencing method suitable for high throughput, reverse genetic analyses of gene function in fern gametophytes

BACKGROUND: Ceratopteris richardii is a useful experimental system for studying gametophyte development and sexual reproduction in plants. However, few tools for cloning mutant genes or disrupting gene function exist for this species. The feasibility of systemic gene silencing as a reverse genetics tool was examined in this study. RESULTS: Several DNA constructs targeting a Ceratopteris protoporphyrin IX magnesium chelatase (CrChlI) gene that is required for chlorophyll biosynthesis were each introduced into young gametophytes by biolistic delivery. Their transient expression in individual cells resulted in a colorless cell phenotype that affected most cells of the mature gametophyte, including the meristem and gametangia. The colorless phenotype was associated with a 7-fold decrease in the abundance of the endogenous transcript. While a construct designed to promote the transient expression of a CrChlI double stranded, potentially hairpin-forming RNA was found to be the most efficient in systemically silencing the endogenous gene, a plasmid containing the CrChlI cDNA insert alone was sufficient to induce silencing. Bombarded, colorless hermaphroditic gametophytes produced colorless embryos following self-fertilization, demonstrating that the silencing signal could be transmitted through gametogenesis and fertilization. Bombardment of young gametophytes with constructs targeting the Ceratopteris filamentous temperature sensitive (CrFtsZ) and uroporphyrin dehydrogenase (CrUrod) genes also produced the expected mutant phenotypes. CONCLUSION: A method that induces the systemic silencing of target genes in the Ceratopteris gametophyte is described. It provides a simple, inexpensive and rapid means to test the functions of genes involved in gametophyte development, especially those involved in cellular processes common to all plants

Monte Carlo Computational Modeling of the Energy Dependence of Atomic Oxygen Undercutting of Protected Polymers

A Monte Carlo computational model has been developed which simulates atomic oxygen attack of protected polymers at defect sites in the protective coatings. The parameters defining how atomic oxygen interacts with polymers and protective coatings as well as the scattering processes which occur have been optimized to replicate experimental results observed from protected polyimide Kapton on the Long Duration Exposure Facility (LDEF) mission. Computational prediction of atomic oxygen undercutting at defect sites in protective coatings for various arrival energies was investigated. The atomic oxygen undercutting energy dependence predictions enable one to predict mass loss that would occur in low Earth orbit, based on lower energy ground laboratory atomic oxygen beam systems. Results of computational model prediction of undercut cavity size as a function of energy and defect size will be presented to provide insight into expected in-space mass loss of protected polymers with protective coating defects based on lower energy ground laboratory testing

An Atmospheric Atomic Oxygen Source for Cleaning Smoke Damaged Art Objects

Soot and other carbonaceous combustion products deposited on the surfaces of porous ceramic, stone, ivory and paper can be difficult to remove and can have potentially unsatisfactory results using wet chemical and/or abrasive cleaning techniques. An atomic oxygen source which operates in air at atmospheric pressure, using a mixture of oxygen and helium, has been developed to produce an atomic oxygen beam which is highly effective in oxidizing soot deposited on surfaces by burning candles made of paraffin, oil or rendered animal fat. Atomic oxygen source operating conditions and the results of cleaning soot from paper, gesso, ivory, limestone and water color-painted limestone are presented

Genetic and Molecular Dissection of Arsenic Hyperaccumulation in the fern Pteris vittata.

Pteris vittata is a fern that is extraordinary in its ability to tolerate hyperaccumulate high levels of arsenic (As). The goals of the proposed research, to identify the genes that are necessary for As hyperaccumulation in P. vittata using molecular and genetic approaches and to understand the physiology of arsenic uptake and distribution in the living plant, were accomplished during the funding period. The genes that have been identified may ultimately enable the engineering or selection of other plants capable of As hyperaccumulation. This is important for the phytoremediation of arsenic-contaminated soils in areas where P. vittata cannot grow

Short summary of research with young people for the development of impactful RSHE 2023

The Women and Equalities Committee inquiry (2016), found sexual harassment and sexual violence in schools to be widespread, facilitated by access to online pornography. UK research found most children have seen pornography by 16, with 75% reporting that pornography did not teach about positive relationships (Martellozzo et al., 2017). Ofsted conducted a rapid review of sexual abuse in schools (Ofsted, 2021), finding serious areas of concern surrounding sexual abuse in school has arisen in the context of child-on-child or peer-on-peer abuse (DFE, 2022; Ofsted, 2021). ‘Everyone’s Invited’ website forum for survivors of sexual abuse testifies to this. UK statutory guidance (DFE, 2019) introduced new mandates around Relationships, Sex and Health Education (RSHE), making this compulsory in secondary schools in England from late 2020. The new mandates regarding RSHE provision, highlight the need for more concerted action to ensure that RSHE is relevant to young people’s needs and is delivered effectively. Our current study aimed to inform future action in this area. Our research questions were as follows:1. What do young people want to learn about consent and pornography in schools? 2. How do young people want to learn about consent and pornography in schools? 3. What kind of RSHE resources and activities can empower young people to forge healthy relationships in their daily lives? Five schools and 62 year 9 students took part in this study, which used a focus group approach and delivered this through a post-it note questions activity, showing of a film 'DARE' made by young people for young people (by two members of the research team), and a quote activity, looking at quotes from previous research (conducted by one member of the research team), upon the impact of pornography upon young people. 12 hours of focus group data was collected. Thematic analysis was used to inform our main findings and themes, which were:Focus on relationships not just biology, deliver consent in more depth, integrate diverse sexuality and gender across content, do not ignore pornography and its impact in young people's lives, use innovative entry points such as film and testimonies to discuss topics, allow time to deliver RSHE and prioritise and ringfence this time, deliver learning across genders, the importance of confidence, openness, respect and adaptability of those delivering RSHE, create enabling environments, that may lead to critical conversations with young people about the things that matter in their lives and which are relatable to them

Duration of Effectiveness of Permethrin-Treated Clothing to Prevent Mosquito Bites Under Simulated Conditions

Presented for World Environmental Health Day, September 26, 2016 in Greenville, North Carolina.Biological hazards such as exposure to ticks and mosquitoes can affect worker health. Permethrin is a repellant/insecticide approved for human use by the Environmental Protection Agency. Permethrin-treated clothing is commercially available to the public. Permethrin-treated clothing (50% cotton/50% nylon) has been shown to retain repellency through 70 washings. Work attire differs between state and consulting foresters, park rangers, etc.; hence, variation in protection from vector borne disease may existThis study was funded by the Southeast Center for Agricultural Health and Injury Prevention (# 3049025288-14-060)