Molecular Insights into the Synergistic Effects of Putrescine and Ammonium on Dinoflagellates.

Ammonium and polyamines are essential nitrogen metabolites in all living organisms. Crosstalk between ammonium and polyamines through their metabolic pathways has been demonstrated in plants and animals, while no research has been directed to explore this relationship in algae or to investigate the underlying molecular mechanisms. Previous research demonstrated that high concentrations of ammonium and putrescine were among the active substances in bacteria-derived algicide targeting dinoflagellates, suggesting that the biochemical inter-connection and/or interaction of these nitrogen compounds play an essential role in controlling these ecologically important algal species. In this research, putrescine, ammonium, or a combination of putrescine and ammonium was added to cultures of three dinoflagellate species to explore their effects. The results demonstrated the dose-dependent and species-specific synergistic effects of putrescine and ammonium on these species. To further explore the molecular mechanisms behind the synergistic effects, transcriptome analysis was conducted on dinoflagellate Karlodinium veneficum treated with putrescine or ammonium vs. a combination of putrescine and ammonium. The results suggested that the synergistic effects of putrescine and ammonium disrupted polyamine homeostasis and reduced ammonium tolerance, which may have contributed to the cell death of K. veneficum. There was also transcriptomic evidence of damage to chloroplasts and impaired photosynthesis of K. veneficum. This research illustrates the molecular mechanisms underlying the synergistic effects of the major nitrogen metabolites, ammonium and putrescine, in dinoflagellates and provides direction for future studies on polyamine biology in algal species.

Risk of hysterectomy at the time of myomectomy: an underestimated surgical risk.

OBJECTIVE: To evaluate the risk of hysterectomy at the time of myomectomy and the associated 30-day postoperative morbidity. DESIGN: Cohort study. PATIENTS: Patients who underwent myomectomies identified from the American College of Surgeons' National Surgical Quality Improvement Program from 2010 to 2021. INTERVENTION: Unplanned hysterectomy at the time of a myomectomy procedure. MAIN OUTCOME MEASURES: The Current Procedural Terminology codes were used to identify myomectomies performed with or without concurrent hysterectomy. Preoperative characteristics and morbidity outcomes were obtained. The univariate analysis was performed using the chi-square and Fisher exact tests, as appropriate. Multivariate logistic regression reported risk factors for individuals who underwent hysterectomy at the time of myomectomy. P values of <.05 were considered statistically significant. RESULTS: A total of 13,213 individuals underwent myomectomy, and 399 (3.0%) had a hysterectomy performed during myomectomy. Concurrent hysterectomy was most frequently performed with the laparoscopic approach (7.1%), followed by the abdominal (3.2%) and hysteroscopic (1.9%) approaches. Age ≥43 years, obesity class II and higher, American Society of Anesthesiologists (ASA) class greater than II, tobacco use, longer operative time (>85 minutes), and laparoscopic approach were associated with a significantly increased risk of hysterectomy. When adjusting for age, body mass index, race, ASA class, case type, surgical approach, operative time, preoperative transfusion, preoperative hematocrit, and high fibroid burden, an increased odds of hysterectomy was noted for white race, longer operative time, ASA class III or higher, obesity, laparoscopic approach, and low fibroid burden. Patients who underwent concurrent hysterectomy had a longer median length of hospital stay (2 vs. 1 day), longer median operative time (161 vs. 126 minutes), increased intraoperative/postoperative blood transfusions (14.5% vs. 9.0%), and higher rates of organ/space surgical site infections (1.5% vs. 0.5%) and return to surgery (2.0% vs. 0.7%) than those who did not (P<.05). The risk of a major complication within 30 days of myomectomy increased in patients who underwent concurrent hysterectomy after adjusting for relevant confounders (adjusted odds ratio, 2.4; 95% confidence interval, 1.8-3.2). CONCLUSION: The risk of hysterectomy during a myomectomy is higher than previously reported. The patient age of ≥43 years, obesity, white race, ASA class III or higher, longer operative time, and laparoscopic approach were associated with higher odds of hysterectomy. Identification of patients with these risk factors can aid in patient counseling and surgical planning, which may help reduce the unexpectedly high rates of hysterectomy at planned myomectomy.

Development of alginate beads for precise environmental release applications: A design of experiment based approach and analysis.

Controlled release of active ingredients are important for drug delivery and more recently environmental applications including modulated dosing of chemical and biological controls. This study demonstrates the importance of investigating various material science factors that can influence the diffusion rates of alginate beads to improve and tune their performance for marine environmental applications. This investigation aimed to design a rational workflow to aid in leveraging alginate bead use as a carrier matrix for releasing a specific active agent into water. Experiments were conducted to focus on the narrow a large list of relevant material formulation parameters, which included chitosan molecular weight, chitosan concentration, calcium concentration, drop height, and bead size. Once the most relevant material preparation methods were screened, a more robust statistic Design of Experiments approach was performed and results determined the important (and unimportant) factors for increasing dye release kinetics in marine water. The process was further streamlined by narrowing the critical experimental factors to a three-level based on the prior analysis: chitosan MW, chitosan concentration, and bead size. Analysis of the collected data indicated that while chitosan MW had a negligible impact (Fstatistic = 0.22), bead size (Fstatistic = 60.33) significantly influenced the diffusion rates based on surface area. However, chitosan MW had minor effects where lower chitosan MW enabled higher product release rates. This case investigation was a novel application of the design of experiment approach towards environmental applications to understand differences in release rates to marine waters for the first time and the workflow provided also serve as the basis for researchers to optimize other environmental applications requiring optimization when it is unknown how a large number of formulation variables will impact performance in different environmental scenarios.

Racial disparities in telehealth use during the coronavirus disease 2019 pandemic.

OBJECTIVE: To investigate the impact of coronavirus disease 2019 on initial infertility consultations. DESIGN: Retrospective cohort. SETTING: Fertility practice in an academic medical center. PATIENTS: Patients presenting for initial infertility consultation between January 2019 and June 2021 were randomly selected for prepandemic (n = 500) and pandemic (n = 500) cohorts. EXPOSURE: Coronavirus disease 2019 pandemic. MAIN OUTCOME MEASURES: The primary outcome was a change in the proportion of African American patients using telehealth after pandemic onset compared with all other patients. Secondary outcomes included presentation to an appointment vs. no-show or cancellation. Exploratory outcomes included appointment length and in vitro fertilization initiation. RESULTS: The prepandemic cohort vs. the pandemic cohort had fewer patients with commercial insurance (64.4% vs. 72.80%) and more African American patients (33.0% vs. 27.0%), although the racial makeup did not differ significantly between the two cohorts. Rates of missed appointments did not differ between the cohorts, but the prepandemic cohort vs. the pandemic cohort was more likely to no-show (49.4% vs. 27.8%) and less likely to cancel (50.6% vs. 72.2%). African American patients, compared with all other patients, during the pandemic were less likely to use telehealth (57.0% vs. 66.8%). African American patients, compared with all other patients, were less likely to have commercial insurance (prepandemic: 41.2% vs. 75.8%; pandemic: 57.0% vs. 78.6%), present to their scheduled appointment (prepandemic: 52.7% vs. 73.7%; pandemic: 48.1% vs. 74.8%), and cancel vs. no-show (prepandemic: 30.8% vs. 68.2%, pandemic: 64.3% vs. 78.3%). On multivariable analysis, African American patients were less likely (odds ratio 0.37, 95% confidence interval 0.28-0.50) and telehealth users were more likely (odds ratio 1.54, 95% confidence interval 1.04-2.27) to present to their appointments vs. no-show or cancel when controlling for insurance type and timing relative to the onset of the pandemic. CONCLUSION: Telehealth implementation during the coronavirus disease 2019 pandemic decreased the overall no-show rate, but this shift did not apply to African American patients. This analysis highlights disparities in insurance coverage, telehealth utilization, and presentation for an initial consultation in the African American population during the pandemic.

Nitrate reductase enzymes in alga Chattonella subsalsa are regulated by environmental cues at the translational and post-translational levels.

Nitrate reductase (NR) catalyzes the rate-limiting step in nitrate assimilation. Plant and algal NRs have a highly conserved domain architecture but differ in regulation. In plants, NR activity is regulated by reversible phosphorylation and subsequent binding of 14-3-3 proteins at a conserved serine residue. Algal NRs typically lack 14-3-3 binding motifs, which have only recently been identified in a few algal species. Previous research indicates that the alga, Chattonella subsalsa, possesses a novel NR, NR2-2/2HbN (NR2), which incorporates a 2/2 hemoglobin domain. A second NR (NR3) in C. subsalsa lacks the cytochrome b5 (heme-Fe) domain but includes a putative binding motif for 14-3-3 proteins. The expression of NR2 and NR3 genes indicates that NR2 transcript abundance was regulated by light, nitrogen source, and temperature, while NR3 transcript levels were only regulated by light. Here, we measured total NR activity in C. subsalsa and the potential for regulation of NR activity by putative 14-3-3 binding proteins. Results indicate that NR activity in C. subsalsa was regulated by light, nitrogen source, and temperature at the translational level. NR activity was also regulated by endogenous rhythm and temperature at the post-translational level, supporting the hypothesis that NR3 is regulated by 14-3-3 binding proteins. Together with a previous report describing the regulation of NR gene expression in C. subsalsa, results suggest that C. subsalsa responds to environmental conditions by differential regulation of NRs at transcriptional, translational, and post-translational levels. This flexibility may provide a competitive advantage for this species in the environment. To date, this is the first report which provides evidence for the potential post-translational regulation of NR by 14-3-3 proteins in algal species and suggests that regulatory mechanisms for NR activity may be shared between plants and some algal species.

Effects of nitrate and ammonium on assimilation of nitric oxide by Heterosigma akashiwo.

The harmful alga Heterosigma akashiwo possesses a hybrid nitrate reductase (NR) enzyme, NR2-2/2HbN, which has the potential to convert NO to nitrate for assimilation into biomass. In previous research, NR transcription in H. akashiwo was induced by nitrate while NR activity was inhibited by ammonium. Here, the capacity of H. akashiwo to use NO in the presence of nitrate and/or ammonium was investigated to understand the regulation of NO assimilation. Continuous cultures of H. akashiwo were acclimated to growth on nitrate, ammonium, or a mixture of both. Aliquots from these cultures were spiked with 15N-labeled NO. The expression of genes involved in nitrogen assimilation was evaluated, as well as nitrate reductase activity and assimilation of 15N-labeled nitrogen into algal biomass. Results showed that NO induced expression and activity of NR, and upregulated expression of GOGAT regardless of the presence of other inorganic nitrogen sources, while GS expression decreased over time. Furthermore, 15NO uptake and assimilation was significantly higher in cultures acclimated for growth on ammonium compared to cultures acclimated for growth on nitrate alone. Assimilation of NO may provide H. akashiwo with a competitive advantage in N-poor environments or areas with elevated NO.

The relationship between anti-Müllerian hormone, body mass index and weight loss: A review of the literature.

Anti-Müllerian hormone (AMH) is commonly used as a proxy for ovarian reserve due to its secretion by antral follicles. It is considered a metric for prediction of ovarian response to certain assisted reproduction therapies. As obesity has a negative impact on fertility, it is important to establish whether obesity-induced hormonal changes influence AMH levels, if and how weight loss affects AMH, and if that influence represents altered reproductive function. The aim of this study was to review the existing literature on the effects of body mass index and weight loss on AMH levels. A PubMed literature keyword search with relevant terms was performed to identify studies that have reported on the AMH/BMI relationship in cohorts with or without polycystic ovarian syndrome (PCOS). A second search was performed to gather publications on weight loss and AMH. Both searches were filtered for all full-text, English-language, adult-female and human-only literature through 1 January 2022. The relationship between AMH and body mass index (BMI) in reproductive-aged women remains inconclusive, with studies in women with and without PCOS producing mixed results. Research in this area is currently limited by failure to analyse the full spectrum of obesity, hindering generalization to a global population increasingly affected by the condition. Some authors pointed to evidence of race/ethnicity as a confounding factor of the relationship, but results between studies are contradictory. Limited evidence on weight loss suggests it may decrease AMH levels despite improving fertility outcomes, particularly after bariatric surgery. The impact of BMI and weight loss on AMH levels has not been conclusively established. Future studies will require appropriate design and sample size calculations, consideration for additional potential confounding factors and inclusion of higher BMIs and a thorough analysis of the full range of obesity.

Algicidal Bacteria: A Review of Current Knowledge and Applications to Control Harmful Algal Blooms.

Interactions between bacteria and phytoplankton in aqueous ecosystems are both complex and dynamic, with associations that range from mutualism to parasitism. This review focuses on algicidal interactions, in which bacteria are capable of controlling algal growth through physical association or the production of algicidal compounds. While there is some evidence for bacterial control of algal growth in the field, our understanding of these interactions is largely based on laboratory culture experiments. Here, the range of these algicidal interactions is discussed, including specificity of bacterial control, mechanisms for activity, and insights into the chemical and biochemical analysis of these interactions. The development of algicidal bacteria or compounds derived from bacteria for control of harmful algal blooms is reviewed with a focus on environmentally friendly or sustainable methods of application. Potential avenues for future research and further development and application of bacterial algicides for the control of algal blooms are presented.

Metabolomic Insights of the Effects of Bacterial Algicide IRI-160AA on Dinoflagellate Karlodinium veneficum.

Shewanella sp. IRI-160 is an algicidal bacterium that secretes an algicide, IRI-160AA. This algicide specifically targets dinoflagellates, while having no adverse effects on other algal species tested. Dinoflagellates exposed to IRI-160AA exhibited increased production of reactive oxygen species (ROS), DNA damage, and cell cycle arrest, implying a programmed pathway leading to cell death (PCD). Here, a metabolomic analysis was conducted on dinoflagellate Karlodinium veneficum and a control cryptophyte species Rhodomonas exposed to IRI-160AA to investigate the cellular mechanisms behind the physiological effects and the specificity of this algicide. Results of this research supported previous observations about physiological responses to the algicide. A suite of metabolites was identified that increased in the cell pellets of K. veneficum but not in Rhodomonas, including oxidative stress biomarkers, antioxidants, and compounds involved in DNA damage and PCD. Overall, the results of this study illustrated the metabolomic mechanisms underlying the algicidal effects of IRI-160AA on dinoflagellates. This research also provided insights and future directions for studies on the cellular response of dinoflagellates exposed to antagonistic bacteria in the environment.

Heterosigma akashiwo does not serve as prey and chloroplast donor for the toxic dinoflagellate, Dinophysis acuminata.

In laboratory culture, the toxic dinoflagellate Dinophysis acuminata acquires plastids from the ciliate, Mesodinium rubrum, which, in turn, acquires plastids from the cryptophyte, Teleaulax amphioxeia. Reports of D. acuminata from field samples found plastids of the raphidophyte, Heterosigma akashiwo within D. acuminata cells, suggesting a broader range of prey. Dinophysis blooms often co-occur with H. akashiwo in Delaware's inland bays. In the study presented here, predation on H. akashiwo by D. acuminata was investigated. Growth rates of D. acuminata were measured when cultured with H. akashiwo either alone or with its known prey, M. rubrum. M. rubrum was also cultured with H. akashiwo to examine predation by the ciliate as a vector for Heterosigma plastids. Ingestion rates by D. acuminata were measured when presented with H. akashiwo as prey, and retention of plastids from H. akashiwo was investigated by measuring chlorophyll a fluorescence intensities in D. acuminata cells presented with H. akashiwo as prey compared to M. rubrum. Additionally, a fluorescence-based method was developed to identify the presence of the accessory pigment fucoxanthin from H. akashiwo plastids in cells of D. acuminata. Results showed that the growth rate of D. acuminata was significantly lower when offered H. akashiwo as prey compared the growth rate when offered M. rubrum as prey. Likewise, no predation was observed when D. acuminata was offered H. akashiwo as prey. Intensity of chlorophyll a fluorescence was lower when H. akashiwo was offered as prey compared to M. rubrum, and fucoxanthin was not detected in any of the Dinophysis cells examined after incubation with H. akashiwo. Results of this investigation do not support the hypothesis that D. acuminata preys on H. akashiwo and highlight the need for further research on factors that stimulate the growth of Dinophysis in field populations.

On the shoulders of giants: perspectives in minimally invasive reproductive surgery.

The purpose of this video is to illustrate the evolution of minimally invasive surgery from the perspectives of several pioneering surgeons in the field of reproductive surgery who, among others, were present during its nascence and exponential growth. Interviews were conducted with five reproductive surgeons who had foundational roles in the innovation of operative laparoscopy and hysteroscopy. Surgeons interviewed include Drs. Victor Gomel, Togas Tulandi, Stephen Corson, Jacques Donnez, and Camran Nezhat. The interviews were conducted using standardized questions and recorded, edited, and grouped both thematically and in sequence to develop an illustration of their perspectives. A diverse array of reproductive surgeons has been instrumental in establishing minimally invasive surgery as a safe and effective means of diagnosing and treating patients with infertility. The transition from laparotomy to laparoscopy consistently has had distinct challenges for each but ultimately led to significant advances in surgical management and improvement in outcomes for patients with infertility and chronic pelvic pain. Through structured interviews from some of our surgical pioneers, they not only recognize their predecessors and contemporaries but also teach us valuable lessons about our history, sparking innovation, and newer surgical applications of reproductive surgery in reproductive endocrinology and infertility practice.

Interactive effects of light, CO2 and temperature on growth and resource partitioning by the mixotrophic dinoflagellate, Karlodinium veneficum.

There is little information on the impacts of climate change on resource partitioning for mixotrophic phytoplankton. Here, we investigated the hypothesis that light interacts with temperature and CO2 to affect changes in growth and cellular carbon and nitrogen content of the mixotrophic dinoflagellate, Karlodinium veneficum, with increasing cellular carbon and nitrogen content under low light conditions and increased growth under high light conditions. Using a multifactorial design, the interactive effects of light, temperature and CO2 were investigated on K. veneficum at ambient temperature and CO2 levels (25°C, 375 ppm), high temperature (30°C, 375 ppm CO2), high CO2 (30°C, 750 ppm CO2), or a combination of both high temperature and CO2 (30°C, 750 ppm CO2) at low light intensities (LL: 70 µmol photons m-2 s-2) and light-saturated conditions (HL: 140 µmol photons m-2 s-2). Results revealed significant interactions between light and temperature for all parameters. Growth rates were not significantly different among LL treatments, but increased significantly with temperature or a combination of elevated temperature and CO2 under HL compared to ambient conditions. Particulate carbon and nitrogen content increased in response to temperature or a combination of elevated temperature and CO2 under LL conditions, but significantly decreased in HL cultures exposed to elevated temperature and/or CO2 compared to ambient conditions at HL. Significant increases in C:N ratios were observed only in the combined treatment under LL, suggesting a synergistic effect of temperature and CO2 on carbon assimilation, while increases in C:N under HL were driven only by an increase in CO2. Results indicate light-driven variations in growth and nutrient acquisition strategies for K. veneficum that may benefit this species under anticipated climate change conditions (elevated light, temperature and pCO2) while also affecting trophic transfer efficiency during blooms of this species.

Effects of a bacteria-produced algicide on non-target marine invertebrate species.

Harmful algal blooms (HABs) affect both freshwater and marine systems. Laboratory experiments suggest an exudate produced by the bacterium Shewanella sp. IRI-160 could be used to prevent or mitigate dinoflagellate blooms; however, effects on non-target organisms are unknown. The algicide (IRI-160AA) was tested on various ontogenetic stages of the copepod Acartia tonsa (nauplii and adult copepodites), the blue crab Callinectes sapidus (zoea larvae and megalopa postlarvae), and the eastern oyster Crassostrea virginica (pediveliger larvae and adults). Mortality experiments with A. tonsa revealed that the 24-h LC50 was 13.4% v/v algicide for adult females and 5.96% for early-stage nauplii. For C. sapidus, the 24-h LC50 for first-stage zoeae was 16.8%; results were not significant for megalopae or oysters. Respiration rates for copepod nauplii increased in the 11% concentration, and in the 11% and 17% concentrations for crab zoeae; rates of later stages and oysters were unaffected. Activity level was affected for crab zoeae in the 1%, 11%, and 17% treatments, and for oyster pediveliger larvae at the 17% level. Activity of later stages and of adult copepods was unaffected. Smaller, non-target biota with higher surface to volume could be negatively impacted from IRI-160AA dosing, but overall the taxa and stages assayed were tolerant to the algicide at concentrations required for dinoflagellate mortality (EC50 = ~ 1%).

Immobilization of algicidal bacterium Shewanella sp. IRI-160 and its application to control harmful dinoflagellates.

Shewanella sp. IRI-160 is an algicidal bacterium isolated from Delaware Inland Bays. It secretes water-soluble compounds that inhibit the growth of dinoflagellates. Previous research indicated that this bacterium does not have a negative impact on other algal species. In this research, Shewanella sp. IRI-160 was immobilized to different porous matrices, including agarose, alginate hydrogel, cellulosic sponge, and polyester foam. The retention of Shewanella sp. IRI-160 on or within these matrices was examined at 4 and 25 °C for 12 days. Results indicated that alginate was superior in terms of cell retention, with >99% of Shewanella cells retained in the matrix after 12 days. Shewanella sp. IRI-160 cells were then immobilized within alginate beads to evaluate algicidal effects on harmful dinoflagellates Karlodinium veneficum and Prorocentrum minimum at bacterial concentrations of 106 to 108 cells mL-1. The effects on dinoflagellates were compared to non-harmful cryptophyte Rhodomonas sp., as well as the effects of free-living bacteria on these species. Results indicated that immobilized Shewanella sp. IRI-160 in alginate beads were as effective as the free-living bacteria to control the growth of K. veneficum and P. minimum, while no negative impacts of immobilized Shewanella sp. IRI-160 on the non-harmful control species Rhodomonas sp. were observed. Overall, this study suggests that immobilized Shewanella sp. IRI-160 may be used as an environmentally friendly approach to prevent or mitigate the blooms of harmful dinoflagellates and provides insight and directions for future studies.

Functional trait thermal acclimation differs across three species of mid-Atlantic harmful algae.

Characterizing the thermal niche of harmful algae is crucial for understanding and projecting the effects of future climate change on harmful algal blooms. The effects of 6 different temperatures (18-32 °C) on the growth, photophysiology, and toxicity were examined in the dinoflagellate Karlodinium veneficum, and the raphidophytes, Heterosigma akashiwo and Chattonella subsalsa from the Delaware Inland Bays (DIB). K. veneficum and H. akashiwo had skewed unimodal growth patterns, with temperature optima (Topt) at 28.6 and 27.3 °C respectively and an upper thermal niche limit of 32 °C. In contrast, C. subsalsa growth increased linearly with temperature, suggesting Topt and upper thermal boundaries >32 °C. K. veneficum photosystem II (PSII) photochemical efficiency remained stable across all temperatures, while H. akashiwo PSII efficiency declined at higher temperature and C. subsalsa was susceptible to low temperature (~18 °C) photoinactivation. Cell toxicity thermal response was species-specific such that K. veneficum toxicity increased with temperature above Topt. Raphidophyte toxicity peaked at 25-28 °C and was in close agreement with Topt for growth in H. akashiwo but below C. subsalsa maximal growth. The mode of toxicity was markedly different between the dinoflagellate and the raphidophytes such that K. veneficum had greater hemolytic activity while the raphidophytes had pronounced fish gill cell toxicity. These results and patterns of natural abundance for these algae in the DIB suggest that continued ocean warming may contribute to C. subsalsa bloom formation while possibly promoting highly toxic blooms of K. veneficum.

Publisher Correction: Genetic tool development in marine protists: emerging model organisms for experimental cell biology.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.