Fetal ezrin expression affects macrophages and regulatory T cells in mouse placental decidua.

Ezrin is a cross-linker protein between membrane proteins and cytosolic actin, abundantly expressed in the placenta among the ERM protein family. Ezrin gene knockout mice exhibit fetal growth restriction after gestational day (GD) 15.5. This study aimed to clarify the effect of ezrin on immune cells that influence fetal growth and immune tolerance. Ezrin heterozygous knockout (Ez+/-) mice were interbred, and the gene expressions and immune cell distributions in the placentas of wild-type (Ez+/+) and ezrin knockout (Ez-/-) fetuses were analyzed. IL-6 expression in the placenta of Ez-/- fetuses was significantly higher than in Ez+/+ fetuses at GD 15.5. The mRNA expression of IL-6 in the uterine decidua attached to Ez-/- fetuses was higher compared to that attached to Ez+/+ fetuses but not in the junctional zone and labyrinth. Classical M1 and M2 macrophages in the decidua were analyzed by flow cytometry using CD86 and CD206 as markers. M1 macrophages increased in the decidua attached to Ez-/- mice compared to Ez+/+ mice, while M2 macrophages did not increase. CD4-positive T cells showed a reduction in the decidua attached to Ez-/- fetuses. Further analysis involved the subcutaneous administration of tacrolimus in pregnant Ez+/- mice from GD 8.5 to GD 15.5, which prevented the decrease in fetal body weight and decidual CD4-positive T cells in Ez-/- mice at GD 15.5. These results suggest that impaired expression of fetoplacental-derived ezrin induces inflammatory conditions in the uterine decidua through M1 polarization of macrophages, increased IL-6, and decreased CD4-positive T cells, including Treg cells.

Phagotrophy in the nitrogen-fixing haptophyte Braarudosphaera bigelowii.

Biological nitrogen fixation provides fixed nitrogen for microbes living in the oligotrophic open ocean. UCYN-A2, the previously known symbiont of Braarudosphaera bigelowii, now believed to be an early-stage B. bigelowii organelle that exchanges fixed nitrogen for fixed carbon, is globally distributed. Indirect evidence suggested that B. bigelowii might be a mixotrophic (phagotrophic) phototrophic flagellate. The goal of this study was to determine if B. bigelowii can graze on bacteria using several independent approaches. The results showed that B. bigelowii grazed on co-occurring bacteria at a rate of 5-7 cells/h/B. bigelowii and that the overall grazing rate was significantly higher at nighttime than at daytime. Bacterial abundance changes, assessed with 16S rRNA gene amplicon sequencing analysis, may have indicated preferential grazing by B. bigelowii on specific bacterial genotypes. In addition, Lysotracker™ staining of B. bigelowii suggested digestive activity inside B. bigelowii. Carbon and nitrogen fixation measurements revealed that the carbon demand of B. bigelowii could not be fulfilled by photosynthesis alone, implying supplementation by heterotrophy. These independent lines of evidence together revealed that B. bigelowii engages in phagotrophy, which, beyond serving as a supplementary source of carbon and energy, may also facilitate the indirect assimilation of inorganic nutrients.

Nitrogen-fixing organelle in a marine alga.

Symbiotic interactions were key to the evolution of chloroplast and mitochondria organelles, which mediate carbon and energy metabolism in eukaryotes. Biological nitrogen fixation, the reduction of abundant atmospheric nitrogen gas (N2) to biologically available ammonia, is a key metabolic process performed exclusively by prokaryotes. Candidatus Atelocyanobacterium thalassa, or UCYN-A, is a metabolically streamlined N2-fixing cyanobacterium previously reported to be an endosymbiont of a marine unicellular alga. Here we show that UCYN-A has been tightly integrated into algal cell architecture and organellar division and that it imports proteins encoded by the algal genome. These are characteristics of organelles and show that UCYN-A has evolved beyond endosymbiosis and functions as an early evolutionary stage N2-fixing organelle, or "nitroplast."

Targeted Metabolite Fingerprints of Thirteen Gambierdiscus, Five Coolia and Two Fukuyoa Species.

The genus Gambierdiscus produces an array of bioactive hydrophilic and lipophilic secondary metabolites that range in mode of action and toxicity. In this study, the metabolite fingerprint was mapped for thirteen Gambierdiscus, five Coolia and two Fukuyoa species (34 isolates) by assessing the production of 56 characterised secondary metabolites. Gambierdiscus polynesiensis was the only species to produce Pacific-ciguatoxin-3B (P-CTX3B), P-CTX3C, iso-P-CTX3B/C, P-CTX4A, P-CTX4B and iso-P-CTX4A/B. G. australes produced maitotoxin-1 (MTX-1) and MTX-5, G. cheloniae produced MTX-6 and G. honu produced MTX-7. Ubiquitous production of 44-methylgambierone was observed amongst all the Gambierdiscus isolates, with nine species also producing gambierone. Additional gambierone analogues, including anhydrogambierone (tentatively described herein), were also detected in all Gambierdiscus species, two Coolia and two Fukuyoa species. Gambieroxide was detected in G. lewisii and G. pacificus and gambieric acid A was detected in ten Gambierdiscus species, with G. australes (CAWD381) being the only isolate to produce gambieric acids A-D. This study has demonstrated that the isolates tested to date produce the known CTXs or MTXs, but not both, and highlighted several species that produced 'unknown' compounds displaying characteristics of cyclic polyethers, which will be the focus of future compound discovery efforts.

Conversion of Olmesartan to Olmesartan Medoxomil, A Prodrug that Improves Intestinal Absorption, Confers Substrate Recognition by OATP2B1.

PURPOSE: Olmesartan medoxomil (olmesartan-MX), an ester-type prodrug of the angiotensin II receptor blocker (ARB) olmesartan, is predominantly anionic at intestinal pH. Human organic anion transporting polypeptide 2B1 (OATP2B1) is expressed in the small intestine and is involved in the absorption of various acidic drugs. This study was designed to test the hypothesis that OATP2B1-mediated uptake contributes to the enhanced intestinal absorption of olmesartan-MX, even though olmesartan itself is not a substrate of OATP2B1. METHODS: Tetracycline-inducible human OATP2B1- and rat Oatp2b1-overexpressing HEK 293 cell lines (hOATP2B1/T-REx-293 and rOatp2b1/T-REx-293, respectively) were established to characterize OATP2B1-mediated uptake. Rat jejunal permeability was measured using Ussing chambers. ARBs were quantified by liquid chromatography-tandem mass spectrometry. RESULTS: Significant olmesartan-MX uptake was observed in hOATP2B1/T-REx-293 and rOatp2b1/T-REx-293 cells, whereas olmesartan uptake was undetectable or much lower than olmesartan-MX uptake, respectively. Furthermore, olmesartan-MX exhibited several-fold higher uptake in Caco-2 cells and greater permeability in rat jejunum compared to olmesartan. Olmesartan-MX uptake in hOATP2B1/T-REx-293 cells and in Caco-2 cells was significantly decreased by OATP2B1 substrates/inhibitors such as 1 mM estrone-3-sulfate, 100 µM rifamycin SV, and 100 µM fluvastatin. Rat Oatp2b1-mediated uptake and rat jejunal permeability of olmesartan-MX were significantly decreased by 50 µM naringin, an OATP2B1 inhibitor. Oral administration of olmesartan-MX with 50 µM naringin to rats significantly reduced the area under the plasma concentration-time curve of olmesartan to 76.9%. CONCLUSION: Olmesartan-MX is a substrate for OATP2B1, and the naringin-sensitive transport system contributes to the improved intestinal absorption of olmesartan-MX compared with its parent drug, olmesartan.

Involvement of GAT2/Slc6a13 in hypotaurine uptake at fetal-facing plasma membrane of syncytiotrophoblasts at mid-to-late gestation in rats and mice.

INTRODUCTION: Hypotaurine, a precursor to taurine, is known for its antioxidant properties and is prominently present in fetal plasma and the placenta. Our previous research revealed that ezrin-knockout mice experience fetal growth retardation, coinciding with reduced hypotaurine levels in fetal plasma. This study aims to elucidate the expression and role of hypotaurine transporters within the placenta. METHODS: We employed quantitative RT-PCR to measure mRNA expression of GAT transporter family members in the placenta during mid-to-late gestation. LC/MS/MS was used to analyze the distribution of hypotaurine in different placental subregions. Immunohistochemistry was utilized to examine the localization of GAT2 in mice. Placental hypotaurine uptake from fetal circulation was studied via umbilical perfusion in rats. RESULTS: Among hypotaurine transporters, GAT2 exhibited increased mRNA and protein expression in murine placenta during mid-to-late gestation. Notably, GAT2/Slc6a13 mRNA and hypotaurine were most concentrated in the labyrinth of murine placenta. In contrast, enzymes responsible for hypotaurine synthesis, such as cysteine dioxygenase, cysteine sulfinic acid decarboxylase, and 2-aminoethanethiol dioxygenase, showed minimal expression in the labyrinth. These findings suggest that GAT2 is a key determinant of hypotaurine levels in the placental labyrinth. Immunohistochemical examination unveiled that GAT2 was predominantly localized on the fetal-facing plasma membrane within syncytiotrophoblasts, which co-localized with ezrin. In rat umbilical perfusion experiments, the GAT2/3 and TauT inhibitor, SNAP-5114, significantly reduced hypotaurine extraction from fetal circulation to the placenta. DISCUSSION: The results suggest that GAT2 plays a pivotal role in the concentrative uptake of hypotaurine from fetal plasma within syncytiotrophoblasts of the placenta.

Immunogenicity and protective efficacy of a co-formulated two-in-one inactivated whole virus particle COVID-19/influenza vaccine.

Due to the synchronous circulation of seasonal influenza viruses and severe acute respiratory coronavirus 2 (SARS-CoV-2) which causes coronavirus disease 2019 (COVID-19), there is need for routine vaccination for both COVID-19 and influenza to reduce disease severity. Here, we prepared individual WPVs composed of formalin-inactivated SARS-CoV-2 WK 521 (Ancestral strain; Co WPV) or influenza virus [A/California/07/2009 (X-179A) (H1N1) pdm; Flu WPV] to produce a two-in-one Co/Flu WPV. Serum analysis from vaccinated mice revealed that a single dose of Co/Flu WPV induced antigen-specific neutralizing antibodies against both viruses, similar to those induced by either type of WPV alone. Following infection with either virus, mice vaccinated with Co/Flu WPV showed no weight loss, reduced pneumonia and viral titers in the lung, and lower gene expression of proinflammatory cytokines, as observed with individual WPV-vaccinated. Furthermore, a pentavalent vaccine (Co/qFlu WPV) comprising of Co WPV and quadrivalent influenza vaccine (qFlu WPV) was immunogenic and protected animals from severe COVID-19. These results suggest that a single dose of the two-in-one WPV provides efficient protection against SARS-CoV-2 and influenza virus infections with no evidence of vaccine interference in mice. We propose that concomitant vaccination with the two-in-one WPV can be useful for controlling both diseases.

Breast Cancer Resistance Protein Limits Fetal Transfer of Tadalafil in Mice.

Tadalafil, a phosphodiesterase 5 (PDE5) inhibitor, is a candidate therapeutic agent for fetal growth restriction and hypertensive disorders of pregnancy. In this study, we elucidated the fetal transfer of tadalafil in comparison with that of sildenafil, the first PDE5 inhibitor to be approved. We also examined the contributions of multidrug resistance protein 1 (MDR1) and breast cancer resistance protein (BCRP) to fetal transfer. Tadalafil or sildenafil was administered to wild-type, Mdr1a/b-double-knockout or Bcrp-knockout pregnant mice by continuous infusion from gestational day (GD) 14.5 to 17.5, and the fetal-to-maternal plasma concentration ratio of unbound drug (unbound F/M ratio) was evaluated at GD 17.5. The values of unbound F/M ratio of tadalafil and sildenafil in wild-type mice were 0.80 and 1.6, respectively. The unbound F/M ratio of tadalafil was increased to 1.1 and 1.7 in Mdr1a/b-knockout and Bcrp-knockout mice, respectively, while the corresponding values for sildenafil were equal to or less than that in wild-type mice, respectively. A transcellular transport study revealed that basal-to-apical transport of both tadalafil and sildenafil was significantly higher than transport in the opposite direction in MDCKII-BCRP cells. Our research reveals that tadalafil is a newly identified substrate of human and mouse BCRP, and it appears that the fetal transfer of tadalafil is, at least in part, attributed to the involvement of BCRP within the placental processes in mice. The transfer of sildenafil to the fetus was not significantly constrained by BCRP, even though sildenafil was indeed a substantial substrate for BCRP.

Sub-tropical benthic/epiphytic dinoflagellates of Aotearoa New Zealand and Rangitahua Kermadec Islands.

Temperatures and temperature anomalies have been increasing in the sub-tropical regions of Aotearoa New Zealand and these changes may impact on harmful algal bloom (HAB) events. Benthic and epiphytic dinoflagellates, particularly the toxin producers, are the focus of this study as it is predicted that under future climate conditions they may produce more toxins or marine animals may become more susceptible to them. The results of past expeditions to Rangitahua Kermadec Islands and sampling trips to Northland, Aotearoa New Zealand, are summarised and the results of the most recent trips to both regions are presented. The macroalgal habitats of the dinoflagellates are also characterised. Dinoflagellate species not previously identified in Rangitahua include Coolia canariensis, C. palmyrensis, and C. tropicalis, all identified by DNA sequencing of the large subunit ribosomal RNA region. Gambierdiscus polynesiensis was again isolated and produced 44-methylgambierone and gambierone, and one isolate produced ciguatoxins, the cause of Ciguatera Poisoning. An Ostreopsis tairoto isolate, as analysed by the oxidative cleavage method, produced a palytoxin (PLTX)-like amine oxidation fragment, but when analysed for PLTX-like analogues using a new intact method none were detected indicating an 'unknown' PLTX-like compound is produced by this isolate. Isolates of O. cf. siamensis (Ostreopsis sp. 9), collected in Northland, were also analysed using the oxidative cleavage method, with the common PLTX-like amine fragment and the amide fragment corresponding to bishomoPLTX detected in all isolates. Again, the intact method indicated no detections in the isolates, again suggesting an unknown compound was being produced by these isolates. Prorocentrum hoffmannianum isolates produced okadaic acid (OA) and isoDTX-1 and P. lima isolates produced OA, DTX-1, and isoDTX-1. It is expected that new species of potentially harmful, benthic dinoflagellates will continue to be recorded in Aotearoa New Zealand and the results from Rangitahua provide a guide to the HAB species to expect in sub-tropical Northland as the oceans continue to warm.

Characterization of epitopes of human monoclonal antibodies against cytomegalovirus glycoprotein B for neutralization and antibody-dependent phagocytosis.

As congenital cytomegalovirus (CMV) infections are the leading non-genetic cause of sensorineural hearing loss and significant neurological disabilities in children, the development of CMV vaccines should be given the highest public health priority. Although MF59-adjuvanted glycoprotein B (gB) vaccine (gB/MF59) is safe and immunogenic, its efficacy in terms of protection from natural infection was around 50 % in clinical trials. Although gB/MF59 induced high antibody titers, anti-gB antibodies contributed little to the neutralization of infection. Recent studies have found that non-neutralizing functions, including antibody-dependent phagocytosis of virions and virus-infected cells, are likely to play important roles in pathogenesis and vaccine design. Previously, we isolated human monoclonal antibodies (MAbs) that reacted with the trimeric form of gB ectodomain and found that preferential epitopes for neutralization were present on Domains (Doms) I and II of gB, while there were abundant non-neutralizing antibodies targeting Dom IV. In this study, we analyzed the phagocytosis activities of these MAbs and found the following: 1) MAbs effective for phagocytosis of the virions targeted Doms I and II, 2) the MAbs effective for phagocytosis of the virions and those of virus-infected cells were generally distinct, and 3) the antibody-dependent phagocytosis showed little correlation with neutralizing activities. Taking account of the frequency and levels of neutralization and phagocytosis, incorporation of the epitopes on Doms I and II into developing vaccines is considered desirable for the prevention of viremia.

Morphology and phylogeny of Prorocentrum porosum sp. nov. (Dinophyceae): A new benthic toxic dinoflagellate from the Atlantic and Pacific Oceans.

A new marine benthic toxic Prorocentrum species is described from the tropical/subtropical regions of the Atlantic (Colombian Caribbean Sea and Northeast Brazil) and Pacific (Southern Japan) oceans. Morphological cell structures were examined using light (LM) and scanning electron (SEM) microscopy. Prorocentrum porosum sp. nov. was characterized by 35.9-50.2 µm long and 25.4-45.7 µm deep cells, covered by broadly ovoid symmetric thecal plates. The surface of both thecal plates is smooth and covered by randomly scattered kidney-shaped pores (n = 102-149), rounder towards the center, absent in the central part, and surrounded by a conspicuous marginal ring of about 69-92 evenly spaced pores. Broad V-shaped periflagellar area exhibiting flagellar and accessory pores. The molecular phylogenetic position of P. porosum sp. nov. was inferred using partial LSU rRNA gene (rDNA) and rDNA ITS sequences. This new species branched with high support in a Prorocentrum clade including P. caipirignum, P. hoffmannianum and P. cf. lima (P. lima morphotype 5 sensuZhang et al., 2015). Pairwise comparison of ITS1 and ITS2 transcripts with these closest relatives revealed the presence of compensatory base changes (CBCs), with the exception of P. cf. lima (P. lima morphotype 5), which only showed in ITS2 a hemi-CBC (HCBC) and two base changes that possibly induce a structural modification. Toxin analyses performed in two Colombian and Brazilian strains in the present study detected the presence of low amounts of okadaic acid.

L-type Amino Acid Transporter 1 (SLC7A5)-Mediated Transport of Pregabalin at the Rat Blood-Spinal Cord Barrier and its Sensitivity to Plasma Branched-Chain Amino Acids.

Pregabalin is an anti-neuropathic pain drug inhibiting the α2δ subunit of the voltage-dependent calcium channel in the spinal cord. The aim of this study is to characterize the transport mechanism of pregabalin at the blood-spinal cord barrier (BSCB) by means of in vivo experiments in rats and in vitro studies using primary-cultured rat spinal cord endothelial cells. We isolated endothelial cells by culturing rat spinal cord tissue in the presence of puromycin, and confirmed the expression of BSCB markers such as Cd31, Mdr1a, and Claudin-5. The uptake of pregabalin by primary-cultured rat spinal cord endothelial cells was sodium-independent and was significantly inhibited by L-leucine, 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid, and JPH203. These results suggest the involvement of L-type amino acid transporter (LAT) 1. LAT1 mRNA and protein was expressed in primary-cultured rat spinal cord endothelial cells, which is consistent with LAT1 expression at the BSCB. In the in vivo study, the transfer of pregabalin to rat spinal cord and brain was significantly decreased by the pre-administration of branched chain amino acids (BCAAs), which are endogenous substrates of LAT1. Our results indicate that pregabalin transport across the BSCB is mediated at least in part by LAT1 and is inhibited by plasma BCAAs.

Immunization with inactivated whole virus particle influenza virus vaccines improves the humoral response landscape in cynomolgus macaques.

Although antibody-inducing split virus vaccines (SV) are currently the most effective way to combat seasonal influenza, their efficacy can be modest, especially in immunologically-naïve individuals. We investigated immune responses towards inactivated whole influenza virus particle vaccine (WPV) formulations, predicated to be more immunogenic, in a non-human primate model, as an important step towards clinical testing in humans. Comprehensive analyses were used to capture 46 immune parameters to profile how WPV-induced responses differed to those elicited by antigenically-similar SV formulations. Naïve cynomolgus macaques vaccinated with either monovalent or quadrivalent WPV consistently induced stronger antibody responses and hemagglutination inhibition (HI) antibody titres against vaccine-matched viruses compared to SV formulations, while acute reactogenic effects were similar. Responses in WPV-primed animals were further increased by boosting with the same formulation, conversely to modest responses after priming and boosting with SV. 28-parameter multiplex bead array defined key antibody features and showed that while both WPV and SV induced elevated IgG responses against A/H1N1 nucleoprotein, only WPV increased IgG responses against A/H1N1 hemagglutinin (HA) and HA-Stem, and higher IgA responses to A/H1N1-HA after each vaccine dose. Antibodies to A/H1N1-HA and HA-Stem that could engage FcγR2a and FcγR3a were also present at higher levels after one dose of WPV compared to SV and remained elevated after the second dose. Furthermore, WPV-enhanced antibody responses were associated with higher frequencies of HA-specific B-cells and IFN-γ-producing CD4+ T-cell responses. Our data additionally demonstrate stronger boosting of HI titres by WPV following prior infection and support WPV administered as a priming dose irrespective of the follow up vaccine for the second dose. Our findings thus show that compared to SV vaccination, WPV-induced humoral responses are significantly increased in scope and magnitude, advocating WPV vaccination regimens for priming immunologically-naïve individuals and also in the event of a pandemic outbreak.

Toxicity and growth characteristics of epiphytic dinoflagellate Gambierdiscus silvae in Japan.

The genus Gambierdiscus is a marine benthic/epiphytic dinoflagellate that has been investigated worldwide as the causative agent of ciguatera poisoning (CP). In Japan, CP occurs mainly in the subtropical region and sporadically in the temperate region. To understand the mechanism of CP outbreaks in the coastal regions, identifying the species of Gambierdiscus occurring in the regions and determining their toxicity and growth characteristics, such as growth responses to temperature, salinity, and light intensity, are important. Recently, the occurrence of G. silvae in the Japanese temperate and subtropical regions has been revealed through metabarcoding. However, the toxicity and growth characteristics of G. silvae have not yet been investigated. In this study, three strains of Gambierdiscus were isolated from a depth of 30 m in subtropical waters in Japan and were identified as Gambierdiscus silvae based on morphological characteristics and phylogenetic positions. A dichloromethane soluble fraction (DSF) and aqueous methanol soluble fraction (MSF) of the three strains showed high mouse toxicity by intraperitoneal injection, but only the DSF of the three strains showed toxicity by gavage. All strains grew in the range of 17.5-30 °C and salinity range of 25-40, and grew well at 25 °C and salinity 30. The optimal light intensity for growth of the strains was 42.0-83.0 µmol photons/m2/s. These results suggest that G. silvae has the potential to be widely distributed from temperate to subtropical/ regions and in shallow to deep coastal waters of Japan. Understanding the growth characteristics of this species would be useful in predicting the occurrence of this species in Japanese coastal waters. Finally, the results obtained in this study suggest that G. silvae showing high toxicity is one of the causative agents of CP in Japan, and knowledge of this species would be useful in understanding the mechanism of CP outbreaks in Japan.

Limited Impact of Murine Placental MDR1 on Fetal Exposure of Certain Drugs Explained by Bypass Transfer Between Adjacent Syncytiotrophoblast Layers.

PURPOSE: Multidrug resistance protein 1 (MDR1) is located at the interface between two syncytiotrophoblast layers in rodent placenta, and may influence fetal drug distribution. Here, we quantitatively compare the functional impact per single MDR1 molecule of MDR1 at the placental barrier and blood-brain barrier in mice. METHODS: MDR1A and MDR1B proteins were quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Paclitaxel or digoxin was continuously administered to pregnant Mdr1a-/-/Mdr1b-/- or wild-type mice, and the drug concentrations in the maternal and fetal plasma and maternal brain were quantified by LC-MS/MS. RESULTS: MDR1A and MDR1B proteins are expressed in the membrane of mouse placental labyrinth, and total MDR1 at the placental barrier amounts to about 30% of that at the blood-brain barrier. The fetal-to-maternal plasma concentration ratio of digoxin was only marginally affected in Mdr1a-/-/Mdr1b-/- mice, while that of paclitaxel showed a several-fold increase. No such difference between the two drugs was found in the maternal brain distribution. The impact per single MDR1 molecule on the fetal distribution of digoxin was calculated to be much lower than that on the brain distribution, but this was not the case for paclitaxel. Our pharmacokinetic model indicates that the impact of placental MDR1 is inversely correlated to the ratio of permeability through gap junctions connecting the two syncytiotrophoblast layers to passive diffusion permeability. CONCLUSION: Our findings indicate that murine placental MDR1 has a minimal influence on the fetal concentration of certain substrates, such as digoxin, due to bypass transfer, probably via connexin26 gap junctions.

Horizontal and vertical distribution of Gambierdiscus spp. (Dinophyceae) including novel phylotypes in Japan identified by 18S rDNA metabarcoding.

The genus Gambierdiscus is a marine benthic/epiphytic dinoflagellate considered the causative agent of ciguatera poisoning (CP). Clarifying the geographical distribution of this genus to understand the potential risk of CP is important. Many studies have focused only on the species/phylotype composition of Gambierdiscus in shallow waters, but no study has investigated the species/phylotype composition of the genus in deep waters. In the present study, the distributions of Gambierdiscus species/phylotypes at two depths (2-8 and 30 m) and two sampling sites (temperate and subtropical) in Japan was investigated using high throughput sequencing (HTS) with a newly developed primer set that preferentially amplifies the 18S rDNA V8-V9 region of Alveolata. A phylogenetic analysis using 89 samples collected over three years revealed of ten Gambierdiscus species/phylotypes including not only two species that have not been reported in Japan (G. caribaeus and G. silvae) but also four novel phylotypes (Gambierdiscus spp. Clade II_1, Clade II_2, Clade II_3, and Clade VI_1). Uncorrected genetic distances also supported that these new phylotypes clearly diverged from other Gambierdiscus species. All four new phylotypes, G. caribaeus, and G. silvae were distributed in the subtropical region. Among them, Clade II_2, Clade VI_1, and G. silvae were also distributed in the temperate region. Four species/phylotypes previously reported from Japan showed a similar distribution as reported previously. Among the ten species/phylotypes, Gambierdiscus sp. type 3 and Clade VI_1 were found only in deep waters, whereas five species/phylotypes were observed only in shallow waters. The other three species/phylotypes were found in both deep and shallow waters. The results of the horizontal and vertical distribution suggest that the growth characteristics of each species/phylotypes found in Japan might adapt to the ambient environmental conditions. This study revealed an inclusive assemblage of Gambierdiscus species/phylotypes in Japan through metabarcoding using the Alveolata primer set. In the future, the abundance and toxicities/toxin productions of the newly reported species/phylotypes need to be clarified to understand the mechanism of CP outbreaks in Japan.

Transplacental Pharmacokinetic Model of Digoxin Based on Ex Vivo Human Placental Perfusion Study.

Digoxin is used as first-line therapy to treat fetal supraventricular tachycardia; however, because of the narrow therapeutic window, it is essential to estimate digoxin exposure in the fetus. The data from ex vivo human placental perfusion study are used to predict in vivo fetal exposure noninvasively, but the ex vivo fetal-to-maternal concentration (F:M) ratios observed in digoxin perfusion studies were much lower than those in vivo. In the present study, we developed a human transplacental pharmacokinetic model of digoxin using previously reported ex vivo human placental perfusion data. The model consists of maternal intervillous, fetal capillary, non-perfused tissue, and syncytiotrophoblast compartments, with multidrug resistance protein (MDR) 1 and influx transporter at the microvillous membrane (MVM) and influx and efflux transporters at the basal plasma membrane (BM). The model-predicted F:M ratio was 0.66, which is consistent with the mean in vivo value of 0.77 (95% confidence interval: 0.64-0.91). The time to achieve the steady state from the ex vivo perfusion study was estimated as 1,500 minutes, which is considerably longer than the reported ex vivo experimental durations, and this difference is considered to account for the inconsistency between ex vivo and in vivo F:M ratios. Reported digoxin concentrations in a drug-drug interaction study with MDR1 inhibitors quinidine and verapamil were consistent with the profiles simulated by our model incorporating inhibition of efflux transporter at the BM in addition to MVM. Our modeling and simulation approach should be a powerful tool to predict fetal exposure and DDIs in human placenta. SIGNIFICANCE STATEMENT: We developed a human transplacental pharmacokinetic model of digoxin based on ex vivo human placental perfusion studies in order to resolve inconsistencies between reported ex vivo and in vivo fetal-to-maternal concentration ratios. The model successfully predicted the in vivo fetal exposure to digoxin and the drug-drug interactions of digoxin and P-glycoprotein/multidrug resistance protein 1 inhibitors in human placenta.

Associations between locomotive and non-locomotive physical activity and physical performance in older community-dwelling females with and without locomotive syndrome: a cross-sectional study.

BACKGROUND: Locomotive syndrome (LS) is a condition of reduced mobility due to a disorder of the locomotive system. Increasing moderate to vigorous physical activity (MVPA) has been recommended to prevent LS. However, to increase daily MVPA is difficult for older people with LS. The MVPA consists of not only locomotive activities such as walking but also non-locomotive activities such as household activities. The aim of this study was to examine the associations between locomotive/non-locomotive MVPA and physical performance in older females with and without LS. METHODS: Participants of this cross-sectional study were 143 older community-dwelling Japanese females. The participants were divided into two groups based on the results of the stand-up test: the normal group (NL) (n = 86) and the LS group (n = 57). Both the locomotive and non-locomotive PA seperately measured with its intensity. The intensity of physical activity (PA) was calculated as METs and classified as sedentary behavior (SB 1-1.5 metabolic equivalent tasks (METs)), low-intensity physical activity (LPA 1.6-2.9 METs), and MVPA (≥ 3 METs). For example, locomotive LPA is slow walking speed of 54 m/min, and locomotive MVPA is walking speed of 67 m/min. While non-locomotive LPA is office work and cooking, non-locomotive MVPA is housecleaning. Physical function was evaluated by handgrip strength, walking speed, and 2-step test. RESULTS: Walking speed, hand-grip strength, 2-step test, daily step counts, and all PA measurements were not significantly different between two groups. In the LS, locomotive MVPA (r = 0.293, p < 0.05) and total MVPA (r = 0.299, p < 0.05) was significantly correlated with walking speed, but not in the NL. CONCLUSIONS: Walking speed was positively correlated with locomotive MVPA and total MVPA in the LS group, but not in NL group. This result suggests that slow walking speed in older people with LS occur in connection with lower locomotive MVPA and total MVPA.

Update of the Planktonic Diatom Genus Pseudo-nitzschia in Aotearoa New Zealand Coastal Waters: Genetic Diversity and Toxin Production.

Domoic acid (DA) is produced by almost half of the species belonging to the diatom genus Pseudo-nitzschia and causes amnesic shellfish poisoning (ASP). It is, therefore, important to investigate the diversity and toxin production of Pseudo-nitzschia species for ASP risk assessments. Between 2018 and 2020, seawater samples were collected from various sites around Aotearoa New Zealand, and 130 clonal isolates of Pseudo-nitzschia were established. Molecular phylogenetic analysis of partial large subunit ribosomal DNA and/or internal transcribed spacer regions revealed that the isolates were divided into 14 species (Pseudo-nitzschia americana, Pseudo-nitzschia arenysensis, Pseudo-nitzschia australis, Pseudo-nitzschia calliantha, Pseudo-nitzschia cuspidata, Pseudo-nitzschia delicatissima, Pseudo-nitzschia fraudulenta, Pseudo-nitzschia galaxiae, Pseudo-nitzschia hasleana, Pseudo-nitzschia multiseries, Pseudo-nitzschia multistriata, Pseudo-nitzschia plurisecta, Pseudo-nitzschia pungens, and Pseudo-nitzschia cf. subpacifica). The P. delicatissima and P. hasleana strains were further divided into two clades/subclades (I and II). Liquid chromatography-tandem mass spectrometry was used to assess the production of DA and DA isomers by 73 representative strains. The analyses revealed that two (P. australis and P. multiseries) of the 14 species produced DA as a primary analogue, along with several DA isomers. This study is the first geographical distribution record of P. arenysensis, P.cuspidata, P. galaxiae, and P. hasleana in New Zealand coastal waters.