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A variety of genetic techniques have been devised to determine cell lineage relationships during tissue development. Some of these systems monitor cell lineages spatially and/or temporally without regard to gene expression by the cells, whereas others correlate gene expression with the lineage under study. The GAL4 Technique for Real-time and Clonal Expression (G-TRACE) system allows for rapid, fluorescent protein-based visualization of both current and past GAL4 expression patterns and is therefore amenable to genome-wide expression-based lineage screens. Here we describe the results from such a screen, performed by undergraduate students of the University of California, Los Angeles (UCLA) Undergraduate Research Consortium for Functional Genomics (URCFG) and high school summer scholars as part of a discovery-based education program. The results of the screen, which reveal novel expression-based lineage patterns within the brain, the imaginal disc epithelia, and the hematopoietic lymph gland, have been compiled into the G-TRACE Expression Database (GED), an online resource for use by the Drosophila research community. The impact of this discovery-based research experience on student learning gains was assessed independently and shown to be greater than that of similar programs conducted elsewhere. Furthermore, students participating in the URCFG showed considerably higher STEM retention rates than UCLA STEM students that did not participate in the URCFG, as well as STEM students nationwide.

In yeast, the formation of Ure2 fibrils underlies the prion state [URE3], in which the yeast loses the ability to distinguish good nitrogen sources from bad ones. The Ure2 prion domain is both necessary and sufficient for the formation of amyloid fibrils. Understanding the structure of Ure2 fibrils is important for understanding the propagation not only of the [URE3] prion but also of other yeast prions whose prion domains share similar features, such as the enrichment of asparagine and glutamine residues. Here, we report a structural study of the amyloid fibrils formed by the Ure2 prion domain using site-directed spin labeling and electron paramagnetic resonance (EPR) spectroscopy. We completed a spin label scanning of all the residue positions between 2 and 80 of the Ure2 prion domain. The EPR data show that the Ure2 fibril core consists of residues 8–68 and adopts a parallel in-register β-sheet structure. Most of the residues show strong spin–exchange interactions, suggesting that there are only short turns and no long loops in the fibril core. Based on the strength of spin–exchange interactions, we determined the likely locations of the β-strands. EPR data also show that the C-terminal region of the Ure2 prion domain is more disordered than the N-terminal region. The roles of hydrophobic and charged residues are analyzed. Overall, the structure of Ure2 fibrils appears to involve a balance of stabilizing interactions, such as asparagine ladders, and destabilizing interactions, such as stacking of charged residues.

Groundwater contamination by arsenic (As) is a serious public health concern in many different areas worldwide, particularly in the Bengal region. Mobilization and fate of As in natural waters is controlled by a variety of factors including the presence of natural organic matter (NOM). This study experimentally determined conditional distribution coefficients (with KD defined as the ratio between As bound to NOM and truly dissolved As) and apparent stability constants between AsIII oxyanions and NOM from cow dung, chicken dung, and Bangladeshi aquaculture pond sediment prior to and after one year of operation. As-sorption experiments with cow dung as the source of NOM resulted in the highest range for log KD, from 4.7 to 6.3. Pond sediment from Bangladesh after a year of operation for fish production showed greater affinity for binding As oxyanions than fresh sediment prior to fish production. PHREEQCI modeling using constants derived from the experiments along with water chemistry parameters typical for the site supports the dominance of AsIII oxyanion-NOM complexation in this system. Models employing constants from previous studies using purified NOM considerably underestimate observed complexation by environmental NOM; thus, applying site-specific constants to geochemical models will better predict As speciation for the field site.

Background The major published clinical guidelines for the management of hypothyroidism and osteoporosis are not uniformly consistent and may be a significant contributor to variability of clinical care delivered by endocrinologists, in addition to other factors, such as physician experience, physician and patient perceptions, and patient comorbidities. The purpose of this study was to assess practice patterns of hypothyroidism and osteoporosis within an academic endocrine clinic. Methods A retrospective medical record review of the first 200 adult patients (n = 100 with primary hypothyroidism and n = 100 with osteoporosis or osteopenia) seen by an endocrinologist beginning January 2, 2017at a large U.S. urban tertiary academic medical center was performed. Data were collected regarding patient demographics, clinic visit type, patterns of ordering laboratory tests and imaging, and choice of pharmacologic treatment. Results Most patients with hypothyroidism (99%) had a serum thyroid stimulating hormone concentration measured. Other thyroid indices measured included serum total thyroxine (10%), serum free thyroxine [T4] (82%), serum free T4 index (6%), serum total triiodothyronine [T3] (9%), and serum free T3 (12%). Forty-eight percent also had serum thyroid antibodies checked. A variety of thyroid hormone supplements were used to treat hypothyroidism, including levothyroxine (83%), levothyroxine and liothyronine combination (8%), and desiccated thyroid extract (6%). In regards to patients with osteoporosis, mean duration of all pharmacologic therapy combined was 73.4 ± 81.9 months. For those with more than one bone density (DXA) scans (64%), the mean time interval between two consecutive DXA scans was variable (mean 32.0 ± 24.7 [SD] months). Sixty eight percent of the patients had bone turnover markers assessed within 7 months of the visit. Conclusions This study reports a real-world experience of endocrinology practice patterns at a large U.S. academic healthcare system. For the common diagnoses of hypothyroidism and osteoporosis, there are opportunities for increased standardization of care, particularly regarding the ordering of laboratory testing and radiologic studies. Identifying areas with significant practice variability may improve the quality and health outcomes and reduce the cost of care for patients with these conditions. Increased understanding regarding the reasons behind ordering various studies may help physician and patients further align their goals.

ObjectiveAbnormal serum liver function tests are common in patients with untreated thyrotoxicosis, even prior to the initiation of antithyroidal medications that may worsen the severity of the abnormal serum liver biochemistries. There is a wide range of the incidence of these abnormalities in the published literature. The aim of this study was to assess the risks factors and threshold of thyrotoxicosis severity for developing an abnormal liver biochemical test upon the diagnosis of new thyrotoxicosis.DesignSingle-institution retrospective cohort study.PatientsPatients of ≥18 years old receiving medical care at a large, academic, urban US medical centre between 2002-2016.MeasurementsInclusion criteria were a serum thyroid stimulating hormone (TSH) concentration of

Formation of amyloid fibrils underlies a wide range of human disorders, including Alzheimer's and prion diseases. The amyloid fibrils can be readily detected thanks to thioflavin T (ThT), a small molecule that gives strong fluorescence upon binding to amyloids. Using the amyloid fibrils of Aβ40 and Aβ42 involved in Alzheimer's disease, and of yeast prion protein Ure2, here we study three aspects of ThT binding to amyloids: quantification of amyloid fibrils using ThT, the optimal ThT concentration for monitoring amyloid formation and the effect of ThT on aggregation kinetics. We show that ThT fluorescence correlates linearly with amyloid concentration over ThT concentrations ranging from 0.2 to 500 µM. At a given amyloid concentration, the plot of ThT fluorescence versus ThT concentration exhibits a bell-shaped curve. The maximal fluorescence signal depends mostly on the total ThT concentration, rather than amyloid to ThT ratio. For the three proteins investigated, the maximal fluorescence is observed at ThT concentrations of 20–50 µM. Aggregation kinetics experiments in the presence of different ThT concentrations show that ThT has little effect on aggregation at concentrations of 20 µM or lower. ThT at concentrations of 50 µM or more could affect the shape of the aggregation curves, but this effect is protein-dependent and not universal.

Background: First-degree relatives of melanoma survivors have a substantially higher lifetime risk for melanoma than individuals with no family history. Exposure to ultraviolet radiation (UVR) is the primary modifiable risk factor for the disease. Reducing UV exposure through sun protection may be particularly important for children with a parental history of melanoma. Nonetheless, limited prior research has investigated sun protection practices and sun exposure among these children. Methods: The California Cancer Registry was used to identify melanoma survivors eligible to participate in a survey to assess their children's sun protection practices and sun exposure. The survey was administered by mail, telephone, or web to Latino and non-Latino white melanoma survivors with at least one child (0–17 years; N = 324). Results: Sun exposure was high and the rate of sunburn was equivalent to or higher than estimates from average-risk populations. Use of sun protection was suboptimal. Latino children were less likely to wear sunscreen and hats and more likely to wear sunglasses, although these differences disappeared in adjusted analyses. Increasing age of the child was associated with lower sun protection and higher risk for sunburn, whereas higher objective risk for melanoma predicted improved sun protection and a higher risk for sunburns. Perception of high barriers to sun protection was the strongest modifiable correlate of sun protection. Conclusions: Interventions to improve sun protection and reduce sun exposure and sunburns in high-risk children are needed. Impact: Intervening in high-risk populations may help reduce the burden of melanoma in the United States. Cancer Epidemiol Biomarkers Prev; 24(1); 169–77. ©2015 AACR.

Biofilms can methylate mercury (Hg) at higher rates than unattached bacteria and are increasingly recognized as important Hg methylation sites in the environment. Our previous study showed that methylation rates in biofilm cultures were up to 1 order of magnitude greater than those in planktonic cultures of a sulfate-reducing bacterium. To probe whether the differential Hg methylation rates resulted from metabolic differences between these two cultures, Hg methylation assays following molybdate or chloroform inhibition (a specific inhibitor of the acetyl-CoA pathway) were conducted on biofilm and planktonic cultures of Desulfovibrio desulfuricans strains M8 and ND132. Molybdate was as effective in inhibiting Hg methylation as well as growth in both planktonic and biofilm cultures. The addition of chloroform only impacted Hg methylation in biofilm cultures, suggesting that different pathways are used for methylation in biofilm compared to planktonic cultures. To investigate this further, expression of the cooS gene, which encodes for carbon monoxide dehydrogenase, a key enzyme in the acetyl-CoA pathway, was compared in biofilm and planktonic cultures of ND132. Biofilm cultures showed up to 4 times higher expression of cooS than planktonic cultures. On the basis of these results, the acetyl-CoA pathway appears to play an important role in methylation in biofilm cultures of this organism, possibly by supplying the methyl group to Hg methylating enzymes; methylation in planktonic cultures appears to be independent of this pathway. This observation has important implications, particularly in developing reliable models to predict Hg methylation rates in different environments and perhaps eventually in being able to control this undesirable chemical transformation.

Monitoring the water quality of recreational beaches is only one step toward understanding microbial contamination -- the primary cause of beach closings. The surf zone sediment reservoir is typically overlooked and may also be important. This study involved monitoring the fecal indicator bacteria (FIB) levels in water and sediment at three ocean beaches (two exposed and one enclosed) during a storm event, conducting laboratory microcosm experiments with sediment from these beaches, and surveying sediment FIB levels at 13 beaches (some exposed and some enclosed). Peaks in Escherichia coli and enterococci concentrations in water and sediment coincided with storm activity at the two exposed beaches, while levels of both FIB were consistently high and irregular at the enclosed beach. Results from microcosm experiments showing similar, dramatic growth of FIB in both overlying water and sediment from all beaches, as well as results from the beach survey, support the hypothesis that the quiescent environment rather than sediment characteristics can explain the elevated sediment FIB levels observed at enclosed beaches. This work has implications for the predictive value of FIB measurements, and points to the importance of the sediment reservoir.