Phylogeny and biogeography of the toxic dinoflagellate Alexandrium

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2003The incidence and known distribution of paralytic shellfish poisoning (PSP) have both increased dramatically in recent decades. A concurrent rise in bloom frequency and geographic range of PSP toxin-producing Alexandrium dinoflagellates explains the increase in PSP, but the reasons for changes in Alexandrium occurrence are unknown. This thesis explores the phylogeny, taxonomy, and biogeography of Alexandrium in light of this recent expansion. Alexandrium phylogeny was reconstructed through rDNA sequence analysis and compared to traditional morphological taxonomy. Alexandrium split into two groups, termed the α and ß clades. Interspecific relationships did not correlate with the morphological traits traditionally used to identify and group species, although other traits appeared phylogenetic ally conserved. The ability to produce toxins has been acquired and/or lost multiple times during Alexandrium evolution. Because most PSP events are caused by either the tamarensis or minutum complexes, the phylogeny, species definitions, and biogeography of each complex was examined. The morphospecies of the tamarensis complex, A. catenella, A. tamarense, and A. fundyense, did not represent valid species by the phylogenetic, biologic or morphological species concepts. Instead, five cryptic species were identified through phylogeny and mating incompatibility. A. universa and A. toxipotens contain all toxic strains, while A. mediterra, A. tamarensis and A. tasmanense contain only non-toxic isolates. Within the minutum group, A. lusitanicum and A. angustitabulatum were also not distinct species based on morphology and phylogeny while A. insuetum and A. tamutum were clearly distinct. Three new minutum group species were identified on the basis of morphology, phylogeny and prior research. Unlike the pattern found for the tamarensis complex, toxic and non-toxic A. minutum strains cannot be segregated based upon LSU sequences. The reconstructed biogeography of the tamarensis and minutum complexes indicate that both natural dispersal and human-assisted transportation of Alexandrium have caused the geographic spread. Human-assisted transport of toxic A. catenella-type cells from Asia to the Thau Lagoon, France, was demonstrated in chapter iv. This thesis demonstrates the importance of human action in the recent PSP increase, better defines species boundaries and provides an invaluable genetic database for tracking future Alexandrium spread and distinguishing between harmful and non-toxic Alexandrium blooms.Financial support was provided by the Woods Hole Oceanographic Institution, the MIT-WHOI Joint Program, a NSF doctoral fellowship, NOAA Grants No. NA960P0099, NA160P1438, NSF Grants No. OCE-9808173, OCE-9415536 and supported by the U.S. ECOHAB Program sponsored by NOAA, the U.S. EP A, NSF, NASA and ONR

Zephyr: The Nineteenth Issue

This is the nineteenth issue of Zephyr, the University of New England\u27s journal of creative expression. Since 2000, Zephyr has published original drawings, paintings, photography, prose, and verse created by current and former members of the University community. Zephyr\u27s Editorial Board is made up exclusively of matriculating students.https://dune.une.edu/zephyr/1552/thumbnail.jp

Clinical Study Individual-, Family-, Community-, and Policy-Level Impact of a School-Based Cardiovascular Risk Detection Screening Program for Children in Underserved, Rural Areas: The CARDIAC Project

The Coronary Artery Risk Detection In Appalachian Communities (CARDIAC) Project has screened more than 80,000 children (10-12 years) for cardiovascular and diabetes risk factors over the past 15 years. Simultaneous referral and intervention efforts have also contributed to the overall program impact. In this study, we examined evidence of programmatic impact in the past decade at the individual, family, community, and policy levels from child screening outcomes, referral rates, participation in subsequent services, and policies that embed the activities of the project as a significant element. Within this period of time, fifth-grade overweight and obesity rates were maintained at a time when rates elsewhere increased. 107 children were referred for additional screening and treatment for probable familial hypercholesterolemia (FH); 82 family members were subsequently screened in family-based screening efforts. 58 grants were distributed throughout the state for community-appropriate obesity intervention. A state wellness policy embedded CARDIAC as the method of assessment and national child cholesterol screening guidelines were impacted by CARDIAC findings. The sustainability and successful impact of this school-based program within a largely underserved, rural Appalachian state are also discussed

The One Health Approach to Toxoplasmosis: Epidemiology, Control, and Prevention Strategies

One Health is a collaborative, interdisciplinary effort that seeks optimal health for people, animals, plants, and the environment. Toxoplasmosis, caused by Toxoplasma gondii, is an intracellular protozoan infection distributed worldwide, with a heteroxenous life cycle that practically affects all homeotherms and in which felines act as definitive reservoirs. Herein, we review the natural history of T. gondii, its transmission and impacts in humans, domestic animals, wildlife both terrestrial and aquatic, and ecosystems. The epidemiology, prevention, and control strategies are reviewed, with the objective of facilitating awareness of this disease and promoting transdisciplinary collaborations, integrative research, and capacity building among universities, government agencies, NGOs, policy makers, practicing physicians, veterinarians, and the general public

Transcriptomic response of the red tide dinoflagellate, Karenia brevis, to nitrogen and phosphorus depletion and addition

<p>Abstract</p> <p>Background</p> <p>The role of coastal nutrient sources in the persistence of <it>Karenia brevis </it>red tides in coastal waters of Florida is a contentious issue that warrants investigation into the regulation of nutrient responses in this dinoflagellate. In other phytoplankton studied, nutrient status is reflected by the expression levels of N- and P-responsive gene transcripts. In dinoflagellates, however, many processes are regulated post-transcriptionally. All nuclear encoded gene transcripts studied to date possess a 5' <it>trans</it>-spliced leader (SL) sequence suggestive, based on the trypanosome model, of post-transcriptional regulation. The current study therefore sought to determine if the transcriptome of <it>K. brevis </it>is responsive to nitrogen and phosphorus and is informative of nutrient status.</p> <p>Results</p> <p>Microarray analysis of N-depleted <it>K. brevis </it>cultures revealed an increase in the expression of transcripts involved in N-assimilation (nitrate and ammonium transporters, glutamine synthetases) relative to nutrient replete cells. In contrast, a transcriptional signal of P-starvation was not apparent despite evidence of P-starvation based on their rapid growth response to P-addition. To study transcriptome responses to nutrient addition, the limiting nutrient was added to depleted cells and changes in global gene expression were assessed over the first 48 hours following nutrient addition. Both N- and P-addition resulted in significant changes in approximately 4% of genes on the microarray, using a significance cutoff of 1.7-fold and p ≤ 10^-4. By far, the earliest responding genes were dominated in both nutrient treatments by pentatricopeptide repeat (PPR) proteins, which increased in expression up to 3-fold by 1 h following nutrient addition. PPR proteins are nuclear encoded proteins involved in chloroplast and mitochondria RNA processing. Correspondingly, other functions enriched in response to both nutrients were photosystem and ribosomal genes.</p> <p>Conclusions</p> <p>Microarray analysis provided transcriptomic evidence for N- but not P-limitation in <it>K. brevis</it>. Transcriptomic responses to the addition of either N or P suggest a concerted program leading to the reactivation of chloroplast functions. Even the earliest responding PPR protein transcripts possess a 5' SL sequence that suggests post-transcriptional control. Given the current state of knowledge of dinoflagellate gene regulation, it is currently unclear how these rapid changes in such transcript levels are achieved.</p

The KMOS3D Survey: Demographics and Properties of Galactic Outflows at z=0.6-2.7

We present a census of ionized gas outflows in 599 normal galaxies at redshift 0.6 < z < 2.7, mostly based on integral field spectroscopy of H alpha, [N II], and [S II] line emission. The sample fairly homogeneously covers the main sequence of star-forming galaxies with masses 9.0 < log(M-*/M-circle dot) < 11.7, and probes into the regimes of quiescent galaxies and starburst outliers. About one-third exhibits the high-velocity component indicative of outflows, roughly equally split into winds driven by star formation (SF) and active galactic nuclei (AGNs). The incidence of SF-driven winds correlates mainly with SF properties. These outflows have typical velocities of similar to 450 km s(-1), local electron densities of n(e) similar to 380 cm(-3), modest mass loading factors of similar to 0.1-0.2 at all galaxy masses, and energetics compatible with momentum driving by young stellar populations. The SF-driven winds may escape from log(M-*/M-circle dot) less than or similar to 10.3 galaxies, but substantial mass, momentum, and energy in hotter and colder outflow phases seem required to account for low galaxy formation efficiencies in the low-mass regime. Faster AGN-driven outflows (similar to 1000-2000 km s(-1)) are commonly detected above log(M-*/M-circle dot) similar to 10.7, in up to similar to 75% of log(M-*/M-circle dot) greater than or similar to 11.2 galaxies. The incidence, strength, and velocity of AGN-driven winds strongly correlates with stellar mass and central concentration. Their outflowing ionized gas appears denser (n(e) similar to 1000 cm(-3)), and possibly compressed and shock-excited. These winds have comparable mass loading factors as the SF-driven winds but carry similar to 10 (similar to 50) times more momentum (energy). The results confirm our previous findings of high-duty-cycle, energy-driven outflows powered by AGN above the Schechter mass, which may contribute to SF quenching.E.S.W. and J.T.M. acknowledge support by the Australian Research Council Center of Excellence for All Sky Astrophysics in Three Dimensions (ASTRO 3D), through project number CE170100013. D.J.W. and M.F. acknowledge the support of the Deutsche Forschungsgemeinschaft via Project ID 3871/1-1 and 3871/1-2. G.B.B. acknowledges support from the Cosmic Dawn Center, which is funded by the Danish National Research Foundation

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure