EPA’s role in promoting water efficiency

The Alliance for Water Efficiency is pleased to appear before you today to offer views on activities and programs to improve water efficiency throughout the United States. We are a North American non‐profit organization, composed of diverse stakeholders with significant experience in water conservation programs and policies. Our mission is to promote the efficient and sustainable use of water, to promote cost‐effective water efficiency measures that will reduce wasteful consumption, reduce the need for additional drinking water and waste water capacity, and provide multiple energy, economic, and environmental benefits. And in that mission, we work closely with staff at the Environmental Protection Agency (EPA). As the nation’s steward of ambient water quality as well as safe drinking water, EPA has promoted water efficiency’s many benefits. Programs have existed for over 20 years in EPA’s Office of Water and Wastewater, albeit modestly funded and staffed

Fighting Back

Without antibiotics and antibacterial chemicals, the human race is at a serious disadvantage, causing us to be once again susceptible to many historically deadly epidemic infections. Nevertheless, antibiotic resistance will continue to increase if nothing is done to impede it. This fast-acting enemy is not one to take lightly. Antibiotic resistance is a growing problem for mankind, but simple steps to halt it can be taken now. Mary Kathryne Dickinson is a freshman Integrated Science and Technology major from Richmond, Virginia. Although she hopes to one day do scientific research in the field of genetics, she also plans to sustain her passion for music, art, and writing

Dorsalization of the neural tube by the non-neural ectoderm

The patterning of cell types along the dorsoventral axis of the spinal cord requires a complex set of inductive signals. While the chordamesoderm is a well-known source of ventralizing signals, relatively little is known about the cues that induce dorsal cell types, including neural crest. Here, we demonstrate that juxtaposition of the non-neural and neural ectoderm is sufficient to induce the expression of dorsal markers, Wnt-1, Wnt-3a and Slug, as well as the formation of neural crest cells. In addition, the competence of neural plate to express Wnt-1 and Wnt-3a appears to be stage dependent, occurring only when neural tissue is taken from stage 8–10 embryos but not from stage 4 embryos, regardless of the age of the non-neural ectoderm. In contrast to the induction of Wnt gene expression, neural crest cell formation and Slug expression can be induced when either stage 4 or stage 8–10 neural plates are placed in contact with the non-neural ectoderm. These data suggest that the non-neural ectoderm provides a signal (or signals) that specifies dorsal cell types within the neural tube, and that the response is dependent on the competence of the neural tissue

Vascular remodeling of the mouse yolk sac requires hemodynamic force

The embryonic heart and vessels are dynamic and form and remodel while functional. Much has been learned about the genetic mechanisms underlying the development of the cardiovascular system, but we are just beginning to understand how changes in heart and vessel structure are influenced by hemodynamic forces such as shear stress. Recent work has shown that vessel remodeling in the mouse yolk sac is secondarily effected when cardiac function is reduced or absent. These findings indicate that proper circulation is required for vessel remodeling, but have not defined whether the role of circulation is to provide mechanical cues, to deliver oxygen or to circulate signaling molecules. Here, we used time-lapse confocal microscopy to determine the role of fluid-derived forces in vessel remodeling in the developing murine yolk sac. Novel methods were used to characterize flows in normal embryos and in embryos with impaired contractility (Mlc2a^(–/–)). We found abnormal plasma and erythroblast circulation in these embryos, which led us to hypothesize that the entry of erythroblasts into circulation is a key event in triggering vessel remodeling. We tested this by sequestering erythroblasts in the blood islands, thereby lowering the hematocrit and reducing shear stress, and found that vessel remodeling and the expression of eNOS (Nos3) depends on erythroblast flow. Further, we rescued remodeling defects and eNOS expression in low-hematocrit embryos by restoring the viscosity of the blood. These data show that hemodynamic force is necessary and sufficient to induce vessel remodeling in the mammalian yolk sa

Review Of Gender Differences In Learning Styles: Suggestions For STEM Education

Women have made great strides in baccalaureate degree obtainment, out numbering men by over 230,000 conferred baccalaureate degrees in 2008. However, the proportion of earned degrees for women in some of the Science, Technology, Engineering, and Mathematics (STEM) courses continues to lag behind male baccalaureate completions (National Science Foundation, 2010). In addition, according to the National Center for Women and Information Technology (NCWIT), only 21% of information and computer science degrees were awarded to women in 2006 (NCWIT, 2007). In the past decade, higher education has experienced a rapid decline in the number of women involved in the information sciences, particularly computer science (Bank, 2007). A number of social and educational factors have been considered barriers to women entering STEM fields and this area has been well studied in the literature. However, research examining the relationship between gender differences and learning styles in the context of these technical fields is limited. According to Kolb (1976), people decide on a major based on how well the norms of the major fit with their individual learning styles. This paper presents gender differences in learning styles and recommends teaching methodologies most preferred for female learners in STEM courses. Further, a survey was administered to ascertain the extent the results of this study support previous findings

Analysis of somitogenesis using multiphoton laser scanning microscopy (MPLSM)

In order to study complex cellular interactions in the developing somite and nervous system, we have been refining techniques for labeling and imaging individual cells within the living vertebrate embryo. Most recently, we have been using MPLSM to analyze cellular behaviors, such as cell migration, filopodial extension, cell process collapse, and neuron pathfinding using time-lapse microscopy in 3-dimensions (3-d). To enhance the efficiency of two-photon excitation in these samples, we have been using a Zeiss LSM 510 NLO fiber delivery system with a Grating Dispersion Compensator (GDC). This system not only offers the convenience of fiber delivery for coupling our Ti:Sapphire laser to the microscope, but also affords us precise control over the pulsewidth of the mode- locked beam. In addition, we have developed a novel peptide/non-cationic lipid gene delivery system to introduce GFP plasmid into somite cells. This approach has allowed us to generate detailed 3-d images of somite cell morphologies at various stages of somite development in a way that best preserves the vitality of the cells being imaged

Characterization of TonB-Dependent Metal Transporters within Neisseria gonorrhoeae

Neisseria gonorrhoeae, the etiologic agent of gonorrhea, utilizes TonB-dependent transporters to import essential nutrients such as iron. Study of TonB-dependent transporters is extremely important due to the fact that they make excellent vaccine targets. In order to learn more about the structure, function, expression, and regulation of selected TonB-dependent transporters, three goals were established for this study. The first goal was to examine the role of two highly conserved regions of TbpB in lipidation. One of the conserved regions of TbpB, the LSAC motif, was shown to be critical for lipidation. The second goal was to determine whether MisR/MisS regulates expression of TbpA and TbpB. MisR/MisS was shown to regulate the expression of TbpA and TbpB. The third goal was to assess the ability of recombinant TdfJ to bind hemin when expressed in E. coli. Recombinant TdfJ was shown to specifically bind hemin when expressed in E. coli

Dishevelled genes mediate a conserved mammalian PCP pathway to regulate convergent extension during neurulation

The planar cell polarity (PCP) pathway is conserved throughout evolution, but it mediates distinct developmental processes. In Drosophila, members of the PCP pathway localize in a polarized fashion to specify the cellular polarity within the plane of the epithelium, perpendicular to the apicobasal axis of the cell. In Xenopus and zebrafish, several homologs of the components of the fly PCP pathway control convergent extension. We have shown previously that mammalian PCP homologs regulate both cell polarity and polarized extension in the cochlea in the mouse. Here we show, using mice with null mutations in two mammalian Dishevelled homologs, Dvl1 and Dvl2, that during neurulation a homologous mammalian PCP pathway regulates concomitant lengthening and narrowing of the neural plate, a morphogenetic process defined as convergent extension. Dvl2 genetically interacts with Loop-tail, a point mutation in the mammalian PCP gene Vangl2, during neurulation. By generating Dvl2 BAC (bacterial artificial chromosome) transgenes and introducing different domain deletions and a point mutation identical to the dsh1 allele in fly, we further demonstrated a high degree of conservation between Dvl function in mammalian convergent extension and the PCP pathway in fly. In the neuroepithelium of neurulating embryos, Dvl2 shows DEP domain-dependent membrane localization, a pre-requisite for its involvement in convergent extension. Intriguing, the Loop-tail mutation that disrupts both convergent extension in the neuroepithelium and PCP in the cochlea does not disrupt Dvl2 membrane distribution in the neuroepithelium, in contrast to its drastic effect on Dvl2 localization in the cochlea. These results are discussed in light of recent models on PCP and convergent extension