Analysis of toxic and non-toxic Alexandrium (Dinophyceae) species using ribosomal RNA gene sequences

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 November 1992Sequences of small subunit (Ss) and large subunit (Ls) ribosomal RNA genes (rDNA) from the marine dinoflagellates Alexandrium tamarense, A. catenella, A. fundyense, A. affine, A. minutum, A. lusitanicum and A. andersoni were compared to assess the organisms' relationships. Cultures represent isolates from North America, Western Europe, Thailand, Japan, Australia and the ballast water of several cargo vessels, and include both toxic and non-toxic strains. An emphasis was placed on the A. tamarense/catenella/fundyense "species complex," a group of morphotypically-similar organisms found in many regions of the world. Two distinct SsrRNA genes, termed the "A gene" and the "B gene," were found in a toxic A. fundyense isolated from eastern North America. The B gene is considered to be a pseudogene. A restriction fragment length polymorphism (RFLP) assay developed to detect the A and B genes revealed five distinct groups of Alexandrium isolates. Three subdivide the A. tamarense/catenella/fundyense complex, but do not correlate with morphospecies designations. The two remaining groups are associated with cultures that clearly differ morphologically from the A. tamarense/ catenella/fundyense group: the fourth group consists of A. affine isolates, and the fifth group is represented by A. minutum, A.lusitanicum and A. andersoni. The B gene was only found in A. tamarense/catenella/ fundyense, but not in all members of this species complex. The B gene is not uniformly distributed among global populations of Alexandrium. All A. tamarense/catenella/fundyense isolates from North America harbor this gene, but it has also been found in some A. tamarense from scattered locations in Japan, as well as in A. tamarense from the ballast water of one cargo vessel which was on a defined run from Japan to Australia. The B gene may be endemic to North American populations of A. tamarense/catenella/fundyense. It is possible that in the recent past North American A. tamarense were introduced to Japanese waters, and cysts of these organisms have been transported from Japan to Australia. A subset of isolates examined using the the RFLP assay were also compared by cloning and sequencing a fragment of their LsrDNA. Eight major classes of LsrDNA sequences, termed "ribotypes," were identified. Five ribotypes subdivide members of the A. tamarense/catenella!fundyense complex; all isolates containing the B gene cluster as one ribotype. The three remaining ribotypes are typified by: 1) A. affine; 2) A. minutum and A. lusitanicum; and, 3) A. andersoni. LsrDNAs from A. minutum and A. lusitanicum are indistinguishable. A. minutum!lusitanicum/andersoni may represent another Alexandrium species complex, analogous to the A. tamarense/catenella/fundyense group. An organisms' ability to produce toxin appears to be correlated with its LsrDNA phylogenetic lineage. Ribotypes ascribed by the LsrDNA sequences are in complete agreement with, and offer a finer-scale resolution of, groups defined by SsrDNA restriction patterns. The SsrDNA RFLP groups and LsrDNA ribotypes are useful species- and population-specific markers. Alexandrium tamarense/catenella/fundyense exist as geneticallydistinct "strains" (populations), not three genetically-distinct species: representatives collected from the same geographic region appear the most similar, regardless of morphotype, whereas those from geographicallyseparated populations are more divergent even when the same morphospecies are compared. Contrary to this general pattern, A. tamarense/catenella from Japan were found to be exceptionally heterogeneous. Ballast water samples show that viable cysts (resting spores) of toxigenic A. tamarense/catenella are being discharged into Australian ports from multiple, genetically-distinct source populations. The rDNA sequences were also used to test theories accounting for the evolution and global dispersal of A. tamarense/catenella/fundyense. Results suggest a monophyletic radiation of these organisms from a common ancestor that included, or gave rise to, multiple morphotypes. Populations appear to have diverged as a result of vicariance (geographic isolation). The co-occurrence of genetically-distinct strains of these organisms is an indication of dispersal. An example of this is seen in Japan where an introduction of North American A. tamarense appears likely. Determining the timing of dispersal events is problematic if based strictly on rDNA sequence similarities, since these molecules undergo change on a scale of millions of years.This work was supported in part by a grant from the National Science Foundation to D. M. Anderson (contract number OCE89- 11226), the Woods Hole Oceanographic Institution Ocean Ventures Fund and the Woods Hole Oceanographic Institution Education Office

Diel transcriptional response of a California Current plankton microbiome to light, low iron, and enduring viral infection.

Phytoplankton and associated microbial communities provide organic carbon to oceanic food webs and drive ecosystem dynamics. However, capturing those dynamics is challenging. Here, an in situ, semi-Lagrangian, robotic sampler profiled pelagic microbes at 4 h intervals over ~2.6 days in North Pacific high-nutrient, low-chlorophyll waters. We report on the community structure and transcriptional dynamics of microbes in an operationally large size class (>5 μm) predominantly populated by dinoflagellates, ciliates, haptophytes, pelagophytes, diatoms, cyanobacteria (chiefly Synechococcus), prasinophytes (chiefly Ostreococcus), fungi, archaea, and proteobacteria. Apart from fungi and archaea, all groups exhibited 24-h periodicity in some transcripts, but larger portions of the transcriptome oscillated in phototrophs. Periodic photosynthesis-related transcripts exhibited a temporal cascade across the morning hours, conserved across diverse phototrophic lineages. Pronounced silica:nitrate drawdown, a high flavodoxin to ferredoxin transcript ratio, and elevated expression of other Fe-stress markers indicated Fe-limitation. Fe-stress markers peaked during a photoperiodically adaptive time window that could modulate phytoplankton response to seasonal Fe-limitation. Remarkably, we observed viruses that infect the majority of abundant taxa, often with total transcriptional activity synchronized with putative hosts. Taken together, these data reveal a microbial plankton community that is shaped by recycled production and tightly controlled by Fe-limitation and viral activity

Interannual variability of Alexandrium fundyense abundance and shellfish toxicity in the Gulf of Maine

Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Elsevier B. V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part II: Topical Studies in Oceanography 52 (2005): 2843-2855, doi:10.1016/j.dsr2.2005.06.020.Six years of oceanographic surveys of Alexandrium fundyense concentrations in the Gulf of Maine are combined with shellfish toxicity records from coastal monitoring stations to assess covariations of these quantities on seasonal to interannual time scales. Annual mean gulf-wide cell abundance varies by less than one order of magnitude during the time interval examined (1993-2002). Fluctuations in gulf-wide annual mean cell abundance and shellfish toxicity are not related in a consistent manner. This suggests that interannual variations in toxicity may be regulated by transport and delivery of offshore cell populations, rather than the absolute abundance of the source populations themselves.We gratefully acknowledge the support of the US ECOHAB Program, sponsored by NOAA, NSF, EPA, NASA, and ONR

Barriers and enablers of implementation of alcohol guidelines with pregnant women: a cross-sectional survey among UK midwives

Background In 2016, the UK Chief Medical Officers revised their guidance on alcohol and advised women to abstain from alcohol if pregnant or planning pregnancy. Midwives have a key role in advising women about alcohol during pregnancy. The aim of this study was to investigate UK midwives’ practices regarding the 2016 Chief Medical Officers Alcohol Guidelines for pregnancy, and factors influencing their implementation during antenatal appointments. Methods Online cross-sectional survey of a convenience sample of UK midwives recruited through professional networks and social media. Data were gathered using an anonymous online questionnaire addressing knowledge of the 2016 Alcohol Guidelines for pregnancy; practice behaviours regarding alcohol assessment and advice; and questions based on the Theoretical Domains Framework (TDF) to evaluate implementation of advising abstinence at antenatal booking and subsequent antenatal appointments. Results Of 842 questionnaire respondents, 58% were aware of the 2016 Alcohol Guidelines of whom 91% (438) cited abstinence was recommended, although 19% (93) cited recommendations from previous guidelines. Nonetheless, 97% of 842 midwives always or usually advised women to abstain from alcohol at the booking appointment, and 38% at subsequent antenatal appointments. Mean TDF domain scores (range 1–7) for advising abstinence at subsequent appointments were highest (indicative of barriers) for social influences (3.65 sd 0.84), beliefs about consequences (3.16 sd 1.13) and beliefs about capabilities (3.03 sd 073); and lowest (indicative of facilitators) for knowledge (1.35 sd 0.73) and professional role and identity (1.46 sd 0.77). Logistic regression analysis indicated that the TDF domains: beliefs about capabilities (OR = 0.71, 95% CI: 0.57, 0.88), emotion (OR = 0.78; 95%CI: 0.67, 0.90), and professional role and identity (OR = 0.69, 95%CI 0.51, 0.95) were strong predictors of midwives advising all women to abstain from alcohol at appointments other than at booking. Conclusions Our results suggest that skill development and reinforcement of support from colleagues and the wider maternity system could support midwives’ implementation of alcohol advice at each antenatal appointment, not just at booking could lead to improved outcomes for women and infants. Implementation of alcohol care pathways in maternity settings are beneficial from a lifecourse perspective for women, children, families, and the wider community

Microbial community transcriptional networks are conserved in three domains at ocean basin scales

Planktonic microbial communities in the ocean are typically dominated by several cosmopolitan clades of Bacteria, Archaea, and Eukarya characterized by their ribosomal RNA gene phylogenies and genomic features. Although the environments these communities inhabit range from coastal to open ocean waters, how the biological dynamics vary between such disparate habitats is not well known. To gain insight into the differential activities of microbial populations inhabiting different oceanic provinces we compared the daily metatranscriptome profiles of related microbial populations inhabiting surface waters of both a coastal California upwelling region (CC) as well as the oligotrophic North Pacific Subtropical Gyre (NPSG). Transcriptional networks revealed that the dominant photoautotrophic microbes in each environment (Ostreococcus in CC, Prochlorococcus in NPSG) were central determinants of overall community transcriptome dynamics. Furthermore, heterotrophic bacterial clades common to both ecosystems (SAR11, SAR116, SAR86, SAR406, and Roseobacter) displayed conserved, genome-wide inter- and intrataxon transcriptional patterns and diel cycles. Populations of SAR11 and SAR86 clades in particular exhibited tightly coordinated transcriptional patterns in both coastal and pelagic ecosystems, suggesting that specific biological interactions between these groups are widespread in nature. Our results identify common diurnally oscillating behaviors among diverse planktonic microbial species regardless of habitat, suggesting that highly conserved temporally phased biotic interactions are ubiquitous among planktonic microbial communities worldwide.Gordon and Betty Moore Foundation (3777)National Science Foundation (U.S.) (Grant EF0424599)Simons Foundation (Simons Collaboration on Ocean Processes and Ecology

Involvement of alcohol in injury cases in rural Sri Lanka:Prevalence and associated factors among in-patients in three primary care hospitals

BACKGROUND: Injuries account for a major proportion of global morbidity and mortality related to alcohol use. Information on the prevalence of alcohol-related injury in rural Sri Lanka is limited. The aims of this study were to determine the burden of alcohol-related injury in a hospital-based sample in rural Sri Lanka and explore factors associated with an increased risk of alcohol-related injury. METHODS: Involvement of alcohol in injury amongst in-patients was assessed in three hospitals in the North Central Province of Sri Lanka over 6 months. Adult (≥ 18 years) patients were eligible. Patients were assessed for: injury characteristics, current alcohol use (in the past year) using the Alcohol Use Disorder Identification Test (AUDIT), and acute intoxication. Patients with a blood alcohol concentration (BAC) reading equivalent of 10 mg/dL (2.17 mmol/L) were considered as having an alcohol-related injury. Binary logistic regression was used to explore association between alcohol-related injury and demographic and injury characteristics. RESULTS: A total of 883 injured patients were eligible and consented to the study. No alcohol use was reported by 487 (55.2%) of patients (35.6% of men, 95.2% of women). Prevalence of alcohol-related injuries was 14.8% overall and 32.8% among current alcohol users. Almost all patients with an alcohol-related injury were male (122/123; 99.2%); 24 (18.8%) of these patients scored positive for possible alcohol dependence. Patients with an alcohol-related injury had significantly higher AUDIT scores (median = 15 vs 6, p < 0.001), were significantly more likely to be aged 26–40 (OR 2.29, 95% CI:1.11, 4.72) or 41–55 years (OR 2.76, 95% CI: 1.29, 5.90) (compared to 18–25 years), to have a transport-related injury (OR 5.14, 95% CI: 2.30, 11.49) (compared to animal/plant sting/bite), and have intentional injuries (OR 3.47, 95% CI: 1.01, 11.87). CONCLUSIONS: One in three injuries among people who drank alcohol in this sample were alcohol-related. In addition, problematic alcohol use was higher among those with alcohol-related injury. Further work is needed to explore whether this prevalence of alcohol-related injury is reflected in other rural settings in Sri Lanka. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12889-022-12958-8

Multispecies diel transcriptional oscillations in open ocean heterotrophic bacterial assemblages

Oscillating diurnal rhythms of gene transcription, metabolic activity, and behavior are found in all three domains of life. However, diel cycles in naturally occurring heterotrophic bacteria and archaea have rarely been observed. Here, we report time-resolved whole-genome transcriptome profiles of multiple, naturally occurring oceanic bacterial populations sampled in situ over 3 days. As anticipated, the cyanobacterial transcriptome exhibited pronounced diel periodicity. Unexpectedly, several different heterotrophic bacterioplankton groups also displayed diel cycling in many of their gene transcripts. Furthermore, diel oscillations in different heterotrophic bacterial groups suggested population-specific timing of peak transcript expression in a variety of metabolic gene suites. These staggered multispecies waves of diel gene transcription may influence both the tempo and the mode of matter and energy transformation in the sea.Gordon and Betty Moore Foundation (GBMF 492.01)Gordon and Betty Moore Foundation (GBMF 3777)National Science Foundation (U.S.) (Grant EF0424599)David & Lucile Packard Foundatio