Myths of the High Medical Cost of Old Age and Dying

The rising costs of medical care in the United States are often erroneously linked to the growing population of older adults. Despite public perception, health care costs associated with aging are limited. Part of the ILC-USA's project on Ageism In America with generous support from the Open Society Institute, this report identifies and dispels seven myths about caring for older people at the end of life

POC Production and Export in the Indian Ocean Sector of the Southern Ocean: A US-China Collaborative Research Program

This proposed work is a study of the biological production and export flux of biogenic matter in response to ventilation of intermediate and deep water masses within the Polar Front zone. It is a collaborative work between the University of Maine and the Chinese Antarctic Research Expedition (CHINARE). The shipboard work is proposed for the Chinese antarctic resupply vessel off Prydz Bay in the Indian Ocean sector. In the austral Spring, this region experiences phytoplankton blooms that are thought to be the result of nutrient transport by the ventilation of intermediate and deep water masses. On an annual basis, it is believed that such blooms are the primary source of particulate organic carbon and biogenic silica flux to the ocean bottom. At this time however no data exists on the amount of particulate organic matter that sinks through the water column, leaving the quantitative relationships between production and export largely undefined in this region. The initial phase of the work consists of setting out a time-series sediment trap mooring at approximately 64 deg S latitude and 73 deg E longitude to take advantage of the historical data set that CHINARE has obtained in this area over the past decade. The biweekly to monthly trap samples will be analyzed for their organic constituents, and in conjunction with primary productivity observations will provide the basic data from which export values can be derived. This work will be carried out in collaboration with the State Oceanic Administration of the People\u27s Republic of China, and the Chinese Antarctic Research Expedition. In addition to providing time on the antarctic resupply vessel, the SOA will sponsor the shipboard primary productivity experiments and the supporting hydrographic measurements. The collaborating American scientists will provide guidance in making these observations to standards developed for the Joint Global Ocean Flux Study, and provide the hardware for the moored sediment trap. There will be a mutual sharing between the U.S. and Chinese investigators of all samples and data sets, and the data analysis will be carried out jointly

Automated Analysis of a Nematode Population-based Chemosensory Preference Assay

The nematode, Caenorhabditis elegans' compact nervous system of only 302 neurons underlies a diverse repertoire of behaviors. To facilitate the dissection of the neural circuits underlying these behaviors, the development of robust and reproducible behavioral assays is necessary. Previous C. elegans behavioral studies have used variations of a "drop test", a "chemotaxis assay", and a "retention assay" to investigate the response of C. elegans to soluble compounds. The method described in this article seeks to combine the complementary strengths of the three aforementioned assays. Briefly, a small circle in the middle of each assay plate is divided into four quadrants with the control and experimental solutions alternately placed. After the addition of the worms, the assay plates are loaded into a behavior chamber where microscope cameras record the worms' encounters with the treated regions. Automated video analysis is then performed and a preference index (PI) value for each video is generated. The video acquisition and automated analysis features of this method minimizes the experimenter's involvement and any associated errors. Furthermore, minute amounts of the experimental compound are used per assay and the behavior chamber's multi-camera setup increases experimental throughput. This method is particularly useful for conducting behavioral screens of genetic mutants and novel chemical compounds. However, this method is not appropriate for studying stimulus gradient navigation due to the close proximity of the control and experimental solution regions. It should also not be used when only a small population of worms is available. While suitable for assaying responses only to soluble compounds in its current form, this method can be easily modified to accommodate multimodal sensory interaction and optogenetic studies. This method can also be adapted to assay the chemosensory responses of other nematode species

Application of the red-shifted channelrhodopsin Chrimson for the Caenorhabditis elegans cGAL bipartite system

Channelrhodopsins are light-gated ion channels that serve as photoreceptors in photosynthetic microbes and have been applied as crucial optogenetic tools in genetic model organisms. When expressed in animals, they enable light-inducible control of ionic membrane permeability, which directly manipulates the activity of neurons expressing the protein. The application of channelrhodopsin-based optogenetics is particularly powerful when used in conjugation with the cGAL (GAL4-UAS) bipartite system (Wang, 2017). The mating of neuron-specific GAL4 driver lines to new channelrhodopsin effector lines could expand the genetic toolkit to perturb and manipulate neural circuits in the organism. Blue light-gated channelrhodopsins have been widely used in C. elegans neurobiology but often have to be performed in lite-1(ce314) mutant backgrounds because short-wavelength blue light is an aversive cue in wild-type animals and directly affects C. elegans neuronal physiology. Previously, a red light-gated variant of channelrhodopsin, termed Chrimson, has been successfully applied in Drosophila and mice, and has recently been codon-optimized for use in C. elegans (Klapoetke, 2014; Schild, 2015). Here, we constructed a Chrimson (15xUAS::chrimson::gfp) cGAL effector line. We introduced the UAS::chrimson::gfp effector DNA construct as an extrachromosomal array into a previously published cGAL pan-neuronal driver line (PS6961 syIs334) and generated integrants on chromosome II (PS8023, syIs503) and chromosome V (PS8024, syIs504) (Table 1) via standard X-ray irradiation. We showed Chrimson-GFP expression in the C. elegans head and tail neurons (Fig. 1A-1D). We also showed that red light could induce a seizure-like motility phenotype in C. elegans expressing Chrimson-GFP in a pan-neuronal manner (videos), while the negative controls expressing only the effector, or without light induction showed regular motility as expected (Table 2). The body curvature maps from normal and seizure-like motilities showed distinct patterns (Fig. 1E and 1F). We report the effector construct of red-light-gated channelrhodopsin Chrimson as an addition to our cGAL toolkit, which could be widely used in future research to overcome the technical restrictions of blue light-gated channelrhodopsins in C. elegans

Effects of ASD-associated daf-18/PTEN missense variants on C. elegans dauer development

The relatively simple nervous system and facile genetics of Caenorhabditis elegans makes it a potential model organism to study the genetic basis of complex neural diseases, such as autism spectrum disorder (ASD). Our previously published study identified conserved human ASD-missense variants in C. elegans orthologs that have a role on morphology, locomotion or fecundity, suggesting C. elegans as an efficient phenotypic model to study conserved ASD variants (Wong et al., 2019). One of the ASD-associated genes screened in this study is daf-18, an ortholog of PTEN. DAF-18/PTEN is a lipid phosphatase protein that dephosphorylates PIP3, a critical lipid second messenger that mediates downstream kinase cascade signaling of the insulin pathway, that in turn regulates expression of genes involved in C. elegans lifespan and dauer formation (Murphy and Hu, 2013). It is reported that the daf-18(e1375) strain, which has a 30–base pairs insertion in the fourth exon, has a dauer defective phenotype (Ogg and Ruvkun, 1998); however, the effect of daf-18/PTEN single amino acid substitution in dauer formation has not been evaluated before. Here, we investigate the dauer entry abilities of previously published ASD-associated daf-18/PTEN missense variants (Wong et al., 2019). We performed a dauer-entry assay using crude pheromone as a proxy for high population density and heat-killed bacteria as a limited food source. We first determined the crude pheromone concentration required to induce 50% of wild type (N2) strain to enter dauer stage (EC50). Using the calculated EC50value we evaluated each mutant strain in two independent experiments (Table 1). To control day-to-day variations caused by environmental conditions, N2 controls were used in every trail. Additionally, we used the previously reported daf-18 dauer-defective strain (e1375) as a control (Ogg and Ruvkun, 1998). To analyze the obtained data, we performed one-way ANOVA followed by multiple comparisons test (Dunnett test) (Figure 1A). Table 1 Evaluated ASD-associated daf-18/PTEN mutant strains. Strain name PS7439 PS7432 PS7436 PS7430 PS7434 C. elegans allele name daf-18(sy879) daf-18(sy887) daf-18(sy881) daf-18(sy885) daf-18(sy882) C. elegans protein change D66E L115V H138R H168Q T176I Human protein change D22E L70V H93R H123Q T131I As expected, we observed statistically significant difference between our wild type and dauer defective control (e1375). Our results show that H138R (PS7436) and T176I (PS7434) daf-18 mutant strains have a significant difference from the wild type control, and a non-significant difference from the dauer defective control, suggesting these missense alleles cause dauer defective phenotypes to the same level of the e1375 strain. In contrast, we found the D66E (PS7439), L115V (PS7432) and H168Q (PS7430) mutant strains are significantly different from the dauer defective control and not significantly different from the wild type control, suggesting these three missense alleles do not cause the same level of dauer defective phenotype as the defective control does. Altogether, our current data show that H138R and T176I are defective in dauer entry, while D66E, L115V and H168Q daf-18 mutant strains are not (Figure 1A). The Conserved Domain Database (Conserved Domain Search) of NCBI (ID: G5EE01) predicts that four of the five missense variations evaluated in this study are located in the phosphatase domain of DAF-18/PTEN(Figure 1B). It is predicted that amino acid Histidine 138 is located in the active site of the protein, suggesting that H138R (PS7436) amino acid change might have an impact on PIP3 substrate specificity, which could explain the dauer defect phenotype observed. Moreover, it is predicted that both amino acid Histidine 168 and Threonine 176 are located close to the catalytic site of the phosphatase domain. We found a dauer defective phenotype resulting from a T176I substitution (PS7434) but not from a H168Q amino acid substitution (PS7430). These data suggest that certain amino acids in the catalytic and active sites of DAF-18/PTEN decrease the function of the protein, in turn regulating C. elegans dauer development. Future evaluation of PIP3 phosphorylation levels could confirm the effect of these variations on the phosphatase activity. The results of this study contribute to the knowledge of the mechanisms controlling C. elegans dauer entry, and to the C. elegans phenotype-screening of conserved ASD variations

Effects of ASD-associated daf-18/PTEN missense variants on C. elegans dauer development

The relatively simple nervous system and facile genetics of Caenorhabditis elegans makes it a potential model organism to study the genetic basis of complex neural diseases, such as autism spectrum disorder (ASD). Our previously published study identified conserved human ASD-missense variants in C. elegans orthologs that have a role on morphology, locomotion or fecundity, suggesting C. elegans as an efficient phenotypic model to study conserved ASD variants (Wong et al., 2019). One of the ASD-associated genes screened in this study is daf-18, an ortholog of PTEN. DAF-18/PTEN is a lipid phosphatase protein that dephosphorylates PIP3, a critical lipid second messenger that mediates downstream kinase cascade signaling of the insulin pathway, that in turn regulates expression of genes involved in C. elegans lifespan and dauer formation (Murphy and Hu, 2013). It is reported that the daf-18(e1375) strain, which has a 30–base pairs insertion in the fourth exon, has a dauer defective phenotype (Ogg and Ruvkun, 1998); however, the effect of daf-18/PTEN single amino acid substitution in dauer formation has not been evaluated before. Here, we investigate the dauer entry abilities of previously published ASD-associated daf-18/PTEN missense variants (Wong et al., 2019). We performed a dauer-entry assay using crude pheromone as a proxy for high population density and heat-killed bacteria as a limited food source. We first determined the crude pheromone concentration required to induce 50% of wild type (N2) strain to enter dauer stage (EC50). Using the calculated EC50value we evaluated each mutant strain in two independent experiments (Table 1). To control day-to-day variations caused by environmental conditions, N2 controls were used in every trail. Additionally, we used the previously reported daf-18 dauer-defective strain (e1375) as a control (Ogg and Ruvkun, 1998). To analyze the obtained data, we performed one-way ANOVA followed by multiple comparisons test (Dunnett test) (Figure 1A). Table 1 Evaluated ASD-associated daf-18/PTEN mutant strains. Strain name PS7439 PS7432 PS7436 PS7430 PS7434 C. elegans allele name daf-18(sy879) daf-18(sy887) daf-18(sy881) daf-18(sy885) daf-18(sy882) C. elegans protein change D66E L115V H138R H168Q T176I Human protein change D22E L70V H93R H123Q T131I As expected, we observed statistically significant difference between our wild type and dauer defective control (e1375). Our results show that H138R (PS7436) and T176I (PS7434) daf-18 mutant strains have a significant difference from the wild type control, and a non-significant difference from the dauer defective control, suggesting these missense alleles cause dauer defective phenotypes to the same level of the e1375 strain. In contrast, we found the D66E (PS7439), L115V (PS7432) and H168Q (PS7430) mutant strains are significantly different from the dauer defective control and not significantly different from the wild type control, suggesting these three missense alleles do not cause the same level of dauer defective phenotype as the defective control does. Altogether, our current data show that H138R and T176I are defective in dauer entry, while D66E, L115V and H168Q daf-18 mutant strains are not (Figure 1A). The Conserved Domain Database (Conserved Domain Search) of NCBI (ID: G5EE01) predicts that four of the five missense variations evaluated in this study are located in the phosphatase domain of DAF-18/PTEN(Figure 1B). It is predicted that amino acid Histidine 138 is located in the active site of the protein, suggesting that H138R (PS7436) amino acid change might have an impact on PIP3 substrate specificity, which could explain the dauer defect phenotype observed. Moreover, it is predicted that both amino acid Histidine 168 and Threonine 176 are located close to the catalytic site of the phosphatase domain. We found a dauer defective phenotype resulting from a T176I substitution (PS7434) but not from a H168Q amino acid substitution (PS7430). These data suggest that certain amino acids in the catalytic and active sites of DAF-18/PTEN decrease the function of the protein, in turn regulating C. elegans dauer development. Future evaluation of PIP3 phosphorylation levels could confirm the effect of these variations on the phosphatase activity. The results of this study contribute to the knowledge of the mechanisms controlling C. elegans dauer entry, and to the C. elegans phenotype-screening of conserved ASD variations

cGAL, a temperature-robust GAL4–UAS system for Caenorhabditis elegans

The GAL4–UAS system is a powerful tool for manipulating gene expression, but its application in Caenorhabditis elegans has not been described. Here we systematically optimize the system's three main components to develop a temperature-optimized GAL4–UAS system (cGAL) that robustly controls gene expression in C. elegans from 15 to 25 °C. We demonstrate this system's utility in transcriptional reporter analysis, site-of-action experiments and exogenous transgene expression; and we provide a basic driver and effector toolkit

Biology and genome of a newly discovered sibling species of Caenorhabditis elegans

A ‘sibling’ species of the model organism Caenorhabditis elegans has long been sought for use in comparative analyses that would enable deep evolutionary interpretations of biological phenomena. Here, we describe the first sibling species of C. elegans, C. inopinata n. sp., isolated from fig syconia in Okinawa, Japan. We investigate the morphology, developmental processes and behaviour of C. inopinata, which differ significantly from those of C. elegans. The 123-Mb C. inopinata genome was sequenced and assembled into six nuclear chromosomes, allowing delineation of Caenorhabditis genome evolution and revealing unique characteristics, such as highly expanded transposable elements that might have contributed to the genome evolution of C. inopinata. In addition, C. inopinata exhibits massive gene losses in chemoreceptor gene families, which could be correlated with its limited habitat area. We have developed genetic and molecular techniques for C. inopinata; thus C. inopinata provides an exciting new platform for comparative evolutionary studies

cGAL, a temperature-robust GAL4–UAS system for Caenorhabditis elegans

The GAL4–UAS system is a powerful tool for manipulating gene expression, but its application in Caenorhabditis elegans has not been described. Here we systematically optimize the system's three main components to develop a temperature-optimized GAL4–UAS system (cGAL) that robustly controls gene expression in C. elegans from 15 to 25 °C. We demonstrate this system's utility in transcriptional reporter analysis, site-of-action experiments and exogenous transgene expression; and we provide a basic driver and effector toolkit

Screening of deafness-causing DNA variants that are common in patients of European ancestry using a microarray-based approach

The unparalleled heterogeneity in genetic causes of hearing loss along with remarkable differences in prevalence of causative variants among ethnic groups makes single gene tests technically inefficient. Although hundreds of genes have been reported to be associated with nonsyndromic hearing loss (NSHL), GJB2, GJB6, SLC26A4, and mitochondrial (mt) MT-RNR1 and MTTS are the major contributors. In order to provide a faster, more comprehensive and cost effective assay, we constructed a DNA fluidic array, CapitalBioMiamiOtoArray, for the detection of sequence variants in five genes that are common in most populations of European descent. They consist of c.35delG, p.W44C, p.L90P, c.167delT (GJB2); 309kb deletion (GJB6); p.L236P, p.T416P (SLC26A4); and m.1555A>G, m.7444G>A (mtDNA). We have validated our hearing loss array by analyzing a total of 160 DNAs samples. Our results show 100% concordance between the fluidic array biochip-based approach and the established Sanger sequencing method, thus proving its robustness and reliability at a relatively low cost