Prey Lysate Enhances Growth and Toxin Production in an Isolate of Dinophysis acuminata

The physiological and toxicological characteristics of Dinophysis acuminata have been increasingly studied in an attempt to better understand and predict diarrhetic shellfish poisoning (DSP) events worldwide. Recent work has identified prey quantity, organic nitrogen, and ammonium as likely contributors to increased Dinophysis growth rates and/or toxicity. Further research is now needed to better understand the interplay between these factors, for example, how inorganic and organic compounds interact with prey and a variety of Dinophysis species and/or strains. In this study, the exudate of ciliate prey and cryptophytes were investigated for an ability to support D. acuminata growth and toxin production in the presence and absence of prey, i.e., during mixotrophic and phototrophic growth respectively. A series of culturing experiments demonstrated that the addition of ciliate lysate led to faster dinoflagellate growth rates (0.25 +/- 0.002/d) in predator-prey co-incubations than in treatments containing (1) similar levels of prey but without lysate (0.21 +/- 0.003/d), (2) ciliate lysate but no live prey (0.12 +/- 0.004/d), or (3) monocultures of D. acuminata without ciliate lysate or live prey (0.01 +/- 0.007/d). The addition of ciliate lysate to co-incubations also resulted in maximum toxin quotas and extracellular concentrations of okadaic acid (OA, 0.11 +/- 0.01 pg/cell; 1.37 +/- 0.10 ng/mL) and dinophysistoxin-1 (DTX1, 0.20 +/- 0.02 pg/cell; 1.27 +/- 0.10 ng/mL), and significantly greater total DSP toxin concentrations (intracellular + extracellular). Pectenotoxin-2 values, intracellular or extracellular, did not show a clear trend across the treatments. The addition of cryptophyte lysate or whole cells, however, did not support dinoflagellate cell division. Together these data demonstrate that while certain growth was observed when only lysate was added, the benefits to Dinophysis were maximized when ciliate lysate was added with the ciliate inoculum (i.e., during mixotrophic growth). Extrapolating to the field, these culturing studies suggest that the presence of ciliate exudate during co-occurring dinoflagellate-ciliate blooms may indirectly and directly exacerbate D. acuminata abundance and toxigenicity. More research is required, however, to understand what direct or indirect mechanisms control the predator-prey dynamic and what component(s) of ciliate lysate are being utilized by the dinoflagellate or other organisms (e.g., ciliate or bacteria) in the culture if predictive capabilities are to be developed and management strategies created

Toxin profiles of five geographical isolates of Dinophysis spp. from North and South America

This paper is not subject to U.S. copyright. The definitive version was published in Toxicon 57 (2011): 275-187, doi:10.1016/j.toxicon.2010.12.002.Marine dinoflagellates of the genus Dinophysis can produce toxins of the okadaic acid (OA) and pectenotoxin (PTX) groups. These lipophilic toxins accumulate in filter-feeding shellfish and cause an illness in consumers called diarrhetic shellfish poisoning (DSP). In 2008, a bloom of Dinophysis led to the closure of shellfish harvesting areas along the Texas coast, one of the first DSP-related closures in the U.S. This event resulted in a broad study of toxin production in isolates of Dinophysis spp. from U.S. waters. In the present study, we compared toxin profiles in geographical isolates of Dinophysis collected in the U.S. (Eel Pond, Woods Hole MA; Martha’s Vineyard, MA; and Port Aransas Bay, Texas), and in those from Canada (Blacks Harbour, Bay of Fundy) and Chile (Reloncavi Estuary), when cultured in the laboratory under the same conditions. For each isolate, the mitochondrial cox1 gene was sequenced to assist in species identification. Strains from the northeastern U.S. and Canada were all assigned to Dinophysis acuminata, while those from Chile and Texas were most likely within the D. acuminata complex whereas precise species designation could not be made with this marker. Toxins were detected in all Dinophysis isolates and each isolate had a different profile. Toxin profiles of isolates from Eel Pond, Martha’s Vineyard, and Bay of Fundy were most similar, in that they all contained OA, DTX1, and PTX2. The Eel Pond isolate also contained OA-D8 and DTX1-D7, and low levels (unconfirmed structurally) of DTX1-D8 and DTX1-D9. D. acuminata from Martha’s Vineyard produced DTX1-D7, along with OA, DTX1, and PTX2, as identified in both the cells and the culture medium. D. acuminata from the Bay of Fundy produced DTX1 and PTX2, as found in both cells and culture medium, while only trace amounts of OA were detected in the medium. The Dinophysis strain from Texas only produced OA, and the one from Chile only PTX2, as confirmed in both cells and culture medium.Funding was provided by NSF Grant OCE-0850421, the Ocean Life Institute and the Coastal Ocean Institute at the Woods Hole Oceanographic Institution, and the Woods Hole Center for Oceans and Human Health through NSF grant OCE-0430724 and NIEHS grant 1 P50 ES012742. MMT would like to thank the Ministry of Education, People’s Republic of China for financial support as a Grand Fostering Project (No. 707011) and the China Scholarship Council

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Impact of <i>Dinophysis acuminata</i> Feeding <i>Mesodinium rubrum</i> on Nutrient Dynamics and Bacterial Composition in a Microcosm

The development of Dinophysis populations, producers of diarrhetic shellfish toxins, has been attributed to both abiotic (e.g., water column stratification) and biotic (prey availability) factors. An important process to consider is mixotrophy of the Dinophysis species, which is an intensive feeding of the Mesodinium species for nutrients and a benefit from kleptochloroplasts. During the feeding process, the nutritional status in the environment changes due to the preference of Mesodinium and/or Dinophysis for different nutrients, prey cell debris generated by sloppy feeding, and their degradation by micro-organisms changes. However, there is little knowledge about the role of the bacterial community during the co-occurrence of Mesodinium and Dinophysis and how they directly or indirectly interact with the mixotrophs. In this study, laboratory experiments were performed to characterize the environmental changes including those of the prey present, the bacterial communities, and the ambient dissolved nutrients during the co-occurrence of Mesodinium rubrum and Dinophysis acuminata. The results showed that, during the incubation of the ciliate prey Mesodinium with its predator Dinophysis, available dissolved nitrogen significantly shifted from nitrate to ammonium especially when the population of M. rubrum decayed. Growth phases of Dinophysis and Mesodinium greatly affected the structure and composition of the bacterial community. These changes could be mainly explained by both the changes of the nutrient status and the activity of Dinophysis cells. Dinophysis feeding activity also accelerated the decline of M. rubrum and contamination of cultures with okadaic acid, dinophysistoxin-1, and pectenotoxin-2, but their influence on the prokaryotic communities was limited to the rare taxa (&lt;0.1%) fraction. This suggests that the interaction between D. acuminata and bacteria is species-specific and takes place intracellularly or in the phycosphere. Moreover, a majority of the dominant bacterial taxa in our cultures may also exhibit a metabolic flexibility and, thus, be unaffected taxonomically by changes within the Mesodinium-Dinophysis culture system

Automatic Detection of Display Defects for Smart Meters based on Deep Learning

The smart meter is an essential part of an intelligent grid system. Defects in the LCD screen the smart meters affect their use. Therefore, detection of LCD screen defects of smart meters is of great significance for management and use of smart electricity meters. At present, detection methods are mainly realized by manual detection and automatic detection based on machine vision. However, performance of these two methods is not satisfactory. The fault detection task of a smart meter LCD screen can be divided into two parts: smart meter LCD localization and LCD fault detection. Therefore, this paper proposes a twostage system based on deep learning, which combines YOLOv5 with ResNet34. YOLOv5 is used for smart meter LCD localization and the classification network based on ResNet34 for LCD fault detection. We have constructed an LCD screen localization dataset and an LCD screen defect detection dataset to train and test our model. As a result, our model achieves a defect detection accuracy of 98.9% on the dataset proposed in this paper and can accurately detect the common defects of an LCD screen

Design, fabrication and testing of a high frequency broadband hydroacoustic transducer for sonar systems

A high frequency broadband hydroacoustic transducer was fabricated for applications such as small target detection and fine imaging in sonar systems. The utilization of the structure design of multimode coupling theory is employed to expand the operational bandwidth of the transducer by leveraging the characteristics of 1–3 type piezoelectric composites that possess a broad frequency range. Piezoelectric composite sensitive elements of varying thicknesses were developed through optimization of dimensional parameters using theoretical and finite element simulation analyses. These composite sensitive elements were then bonded to a spiral stepped backing to enable lateral stacking, ultimately resulting in the fabrication of a high frequency broadband hydroacoustic transducer. The outcomes of the underwater performance evaluation indicate that the transducer's central frequency is 310 kHz, with a −3 dB bandwidth capable of reaching 100 kHz. The maximum transmit voltage response is 159 dB, while the maximum receive sensitivity is −182 dB. Additionally, the directional beam opening angle of −3 dB at the center frequency is roughly 9°, which effectively broadens the transducer's bandwidth

Rapid Algae Identification and Concentration Prediction Based on Discrete Excitation Fluorescence Spectra

In this paper, an algal identification and concentration determination method based on discrete excitation fluorescence spectra is proposed for online algae identification and concentration prediction. The discrete excitation fluorescence spectra of eight species of harmful algae from four algal categories were assessed. After determining typical excitation wavelengths according to the distribution of photosynthetic pigments and eliminating strongly correlated wavelengths by applying the hierarchical clustering, seven characteristic excitation wavelengths (405, 435, 470, 490, 535, 555, and 590 nm) were selected. By adding the ratios between feature points (435 and 470 nm, 470 and 490 nm, as well as 535 and 555 nm), standard feature spectra were established for classification. The classification accuracy in pure samples exceeded 95%, and that of dominant algae species in a mixed sample was 77.4%. Prediction of algae concentration was achieved by establishing linear regression models between fluorescence intensity at seven characteristic excitation wavelengths and concentrations. All models performed better at low concentrations, not exceeding the threshold concentration of red tide algae outbreak, which provides a proximate cell density of dominant algal species