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Purpose: The Predicting Myopia Onset and progression (PreMO) risk indicator, developed using data generated from white children in the UK, incorporates age, spherical equivalent refraction (SER), axial length (AL) and parental myopia to stratify the likelihood of developing myopia. This study evaluated the PreMO's predictive accuracy using prospective datasets from independent samples of children in Hong Kong (HK) and an ethnically diverse cohort of children in the United Kingdom., Methods: Non-myopic children (SER > -0.50 D) aged 6-8 and 9-10 years were scored using the PreMO risk indicator framework, integrating baseline cycloplegic SER, AL and parental myopia data. Scores were assigned risk categories as follows: 0 = no risk, 1-3 = low risk, 4-6 = moderate risk and 7-9 = high risk. SER at ≥15 years of age was used to define refractive outcomes as 'myopic' or 'not myopic'. PreMO's predictive accuracy was analysed via Receiver Operator Characteristic curves, with Youden's J-Index identifying the optimal risk score threshold. Sensitivity, specificity and area under the curve were determined and compared with those of singular predictors, that is, SER < +0.75 D and AL ≥ 23.07 mm at 6-8 years., Results: In the cohort of children aged 6-8 years, a PreMO risk score ≥ 4 exhibited high sensitivity in predicting myopia onset in UK (0.97) and HK (0.94) children, with high specificity in UK (0.96) and moderate specificity in HK (0.64) children. In UK children aged 6-8 years, the PreMO outperformed singular predictors such as SER and AL. Among HK children aged 9-10 years, the PreMO score maintained high sensitivity (0.90) and moderate specificity (0.72)., Conclusions: A PreMO risk score ≥ 4 is a strong predictive indicator for future myopia onset, particularly in UK children. Despite high sensitivity in both UK and HK cohorts, specificity varied, indicating the need for contextual application of the tool, particularly in pre-myopic Asian children., (© 2024 The Author(s). Ophthalmic and Physiological Optics published by John Wiley & Sons Ltd on behalf of College of Optometrists.)

Purpose: Previous studies have demonstrated an association between melatonin status and both refractive error and axial length in young adult myopes. This study aimed to determine if this relationship extends to a younger adolescent cohort., Methods: Healthy children aged 12-15 years provided morning saliva samples before attending Ulster University (55°N) for cycloplegic autorefraction and axial length measures. Participants completed questionnaires describing recent sleep habits and physical activity. Salivary melatonin was quantified using high-performance liquid chromatography-tandem mass spectrometry. Data collection for all participants occurred over a 1-week period (April 2021)., Results: Seventy participants aged 14.3 (95% CI: 14.2-14.5) years were categorised by spherical equivalent refraction [SER] (range: -5.38DS to +1.88DS) into two groups; myopic SER ≤ -0.50DS ( n  = 22) or nonmyopic -0.50DS < SER ≤ +2.00DS ( n  = 48). Median morning salivary melatonin levels were 4.52 pg/ml (95% CI: 2.60-6.02) and 4.89 pg/ml (95% CI: 3.18-5.66) for myopic and nonmyopic subjects, respectively, and did not differ significantly between refractive groups ( P  = 0.91). Melatonin levels were not significantly correlated with SER, axial length, sleep, or activity scores (Spearman's rank, all P  > 0.39). Higher levels of physical activity were associated with higher sleep quality (Spearman's rank, ρ  = -0.28, P  = 0.02)., Conclusion: The present study found no significant relationship between morning salivary melatonin levels and refractive error or axial length in young adolescents. This contrasts with outcomes from a previous study of adults with comparable methodology, season of data collection, and geographical location. Prospective studies are needed to understand the discrepancies between adult and childhood findings and evaluate whether melatonin levels in childhood are indicative of an increased risk for future onset of myopia and/or faster axial growth trajectories and myopia progression in established myopes. Future work should opt for a comprehensive dim-light melatonin onset protocol to determine circadian phase., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this paper., (Copyright © 2023 Jane M. Fulton et al.)

Increased anthropogenic nutrient loading has led to eutrophication of aquatic ecosystems, which is the major cause of harmful cyanobacteria blooms. Element stoichiometry of cyanobacteria bloom is subject to nutrient availabilities and may significantly contribute to primary production and biogeochemical cycling. Phycobilisome is the antenna of the photosynthetic pigment apparatus in cyanobacteria, which contains phycobilin pigments (PBPs) and linker proteins. This nitrogen (N)-rich protein complex has the potential to support growth as a N-storage site and may play a major role in the variability of cyanobacteria N stoichiometry. However, the regulation of PBPs during bloom formation remains unclear. We investigated the temporal variation of N allocation into PBPs and element stoichiometry for two ubiquitous cyanobacteria species, Microcystis aeruginosa and Dolichospermum flos-aquae , in a batch culture experiment with different initial N availabilities. Our results indicated that the N allocation into PBPs is species-dependent and tightly regulated by the availability of nutrients fueling population expansion. During the batch culture experiment, different nutrient uptake rates led to distinct stoichiometric imbalances of N and phosphorus (P), which substantially altered cyanobacteria C: N and C: P stoichiometry. Microcystis invested cellular N into PBPs and exhibited greater flexibility in C: N and C: P stoichiometry than D. flos-aquae . The dynamics of such N-rich macromolecules may help explain the N stoichiometry variation during a bloom and the interspecific difference between M. aeruginosa and D. flos-aquae . Our study provides a quantitative understanding of the elemental stoichiometry and the regulation of PBPs for non-diazotrophic and diazotrophic cyanobacteria blooms., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Wang, Wagner, Fulton and Scott.)

Archaeal ANaerobic MEthanotrophs (ANME) facilitate the anaerobic oxidation of methane (AOM), a process that is believed to proceed via the reversal of the methanogenesis pathway. Carbon isotopic composition studies indicate that ANME are metabolically diverse and able to assimilate metabolites including methane, methanol, acetate, and dissolved inorganic carbon (DIC). Our data support the interpretation that ANME in marine sediments at methane seeps assimilate both methane and DIC, and the carbon isotopic compositions of the tetrapyrrole coenzyme F430 and the membrane lipids archaeol and hydroxy-archaeol reflect their relative proportions of carbon from these substrates. Methane is assimilated via the methyl group of CH 3 -tetrahydromethanopterin (H 4 MPT) and DIC from carboxylation reactions that incorporate free intracellular DIC. F430 was enriched in 13 C (mean δ 13 C = -27‰ for Hydrate Ridge and -80‰ for the Santa Monica Basin) compared to the archaeal lipids (mean δ 13 C = -97‰ for Hydrate Ridge and -122‰ for the Santa Monica Basin). We propose that depending on the side of the tricarboxylic acid (TCA) cycle used to synthesize F430, its carbon was derived from 76% DIC and 24% methane via the reductive side or 57% DIC and 43% methane via the oxidative side. ANME lipids are predicted to contain 42% DIC and 58% methane, reflecting the amount of each assimilated into acetyl-CoA. With isotope models that include variable fractionation during biosynthesis for different carbon substrates, we show the estimated amounts of DIC and methane can result in carbon isotopic compositions of - 73‰ to - 77‰ for F430 and - 105‰ for archaeal lipids, values close to those for Santa Monica Basin. The F430 δ 13 C value for Hydrate Ridge was 13 C-enriched compared with the modeled value, suggesting there is divergence from the predicted two carbon source models., (© 2019 John Wiley & Sons Ltd.)

The carbon and nitrogen isotopic signatures of chloropigments and porphyrins from the sediments of redox-stratified lakes and marine basins reveal details of past biogeochemical nutrient cycling. Such interpretations are strengthened by modern calibration studies, and here, we report on the C and N isotopic composition of pigments and nutrients in the water column and surface sediment of redox-stratified Fayetteville Green Lake (FGL; New York). We also report δ 13 C and δ 15 N values for pyropheophytin a (Pphe a) and bacteriochlorophyll e (Bchl e) deposited in the Black Sea during its transition to a redox-stratified basin ca. 7.8 ka. We propose a model for evolving nutrient cycling in the Black Sea from 7.8 to 6.4 ka, informed by the new pigment data from FGL. The seasonal study of water column nutrients and pigments at FGL revealed population dynamics in surface and deep waters that were also captured in the sediments. Biomass was greatest near the chemocline, where cyanobacteria, purple sulfur bacteria (PSB), and green sulfur bacteria (GSB) had seasonally variable populations. Bulk organic matter in the surface sediment, however, was derived mainly from the oxygenated surface waters. Surface sediment pigment δ 13 C and δ 15 N values indicate intact chlorophyll a (Chl a) was derived from near the chemocline, but its degradation product pheophytin a (Phe a) was derived primarily from surface waters. Bacteriopheophytin a (Bphe a) and Bchl e in the sediments came from chemocline populations of PSB and GSB, respectively. The distinctive δ 13 C and δ 15 N values for Chl a, Phe a, and Bphe a in the surface sediment are inputs to an isotopic mixing model that shows their decomposition to a common porphyrin derivative can produce non-specific sedimentary isotope signatures. This model serves as a caveat for paleobiogeochemical interpretations in basins that had diverse populations near a shallow chemocline., (© 2018 John Wiley & Sons Ltd.)

Little Salt Spring (Sarasota County, FL, USA) is a sinkhole with groundwater vents at ~77 m depth. The entire water column experiences sulfidic (~50 μM) conditions seasonally, resulting in a system poised between oxic and sulfidic conditions. Red pinnacle mats occupy the sediment-water interface in the sunlit upper basin of the sinkhole, and yielded 16S rRNA gene clones affiliated with Cyanobacteria, Chlorobi, and sulfate-reducing clades of Deltaproteobacteria. Nine bacteriochlorophyll e homologues and isorenieratene indicate contributions from Chlorobi, and abundant chlorophyll a and pheophytin a are consistent with the presence of Cyanobacteria. The red pinnacle mat contains hopanoids, including 2-methyl structures that have been interpreted as biomarkers for Cyanobacteria. A single sequence of hpnP, the gene required for methylation of hopanoids at the C-2 position, was recovered in both DNA and cDNA libraries from the red pinnacle mat. The hpnP sequence was most closely related to cyanobacterial hpnP sequences, implying that Cyanobacteria are a source of 2-methyl hopanoids present in the mat. The mats are capable of light-dependent primary productivity as evidenced by 13 C-bicarbonate photoassimilation. We also observed 13 C-bicarbonate photoassimilation in the presence of DCMU, an inhibitor of electron transfer to Photosystem II. Our results indicate that the mats carry out light-driven primary production in the absence of oxygen production-a mechanism that may have delayed the oxygenation of the Earth's oceans and atmosphere during the Proterozoic Eon. Furthermore, our observations of the production of 2-methyl hopanoids by Cyanobacteria under conditions of low oxygen and low light are consistent with the recovery of these structures from ancient black shales as well as their paucity in modern marine environments., (© 2017 The Authors. Geobiology Published by John Wiley & Sons Ltd.)

Annual Emiliania huxleyi blooms (along with other coccolithophorid species) play important roles in the global carbon and sulfur cycles. E. huxleyi blooms are routinely terminated by large, host-specific dsDNA viruses, (Emiliania huxleyi Viruses; EhVs), making these host-virus interactions a driving force behind their potential impact on global biogeochemical cycles. Given projected increases in sea surface temperature due to climate change, it is imperative to understand the effects of temperature on E. huxleyi's susceptibility to viral infection and its production of climatically active dimethylated sulfur species (DSS). Here we demonstrate that a 3°C increase in temperature induces EhV-resistant phenotypes in three E. huxleyi strains and that successful virus infection impacts DSS pool sizes. We also examined cellular polar lipids, given their documented roles in regulating host-virus interactions in this system, and propose that alterations to membrane-bound surface receptors are responsible for the observed temperature-induced resistance. Our findings have potential implications for global biogeochemical cycles in a warming climate and for deciphering the particular mechanism(s) by which some E. huxleyi strains exhibit viral resistance.

Coccolithoviruses employ a suite of glycosphingolipids (GSLs) to successfully infect the globally important coccolithophore Emiliania huxleyi. Lipid rafts, chemically distinct membrane lipid microdomains that are enriched in GSLs and are involved in sensing extracellular stimuli and activating signalling cascades through protein-protein interactions, likely play a fundamental role in host-virus interactions. Using combined lipidomics, proteomics and bioinformatics, we isolated and characterized the lipid and protein content of lipid rafts from control E. huxleyi cells and those infected with EhV86, the type strain for Coccolithovirus. Lipid raft-enriched fractions were isolated and purified as buoyant, detergent-resistant membranes (DRMs) in OptiPrep density gradients. Transmission electron microscopy of vesicle morphology, polymerase chain reaction amplification of the EhV major capsid protein gene and immunoreactivity to flotillin antisera served as respective physical, molecular and biochemical markers. Subsequent lipid characterization of DRMs via high performance liquid chromatography-triple quadrapole mass spectrometry revealed four distinct GSL classes. Parallel proteomic analysis confirmed flotillin as a major lipid raft protein, along with a variety of proteins affiliated with host defence, programmed cell death and innate immunity pathways. The detection of an EhV86-encoded C-type lectin-containing protein confirmed that infection occurs at the interface between lipid rafts and cellular stress/death pathways via specific GSLs and raft-associated proteins., (© 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.)

Viruses play a key role in controlling the population dynamics of algae, including Emiliania huxleyi, a globally distributed haptophyte with calcite coccoliths that comprise ca. 50% of the sinking carbonate flux from the surface ocean. Emiliania huxleyi viruses (EhVs) routinely infect and terminate E. huxleyi blooms. EhVs are surrounded by a lipid envelope, which we found to be comprised largely of glycosphingolipids (GSLs) with lesser amounts of polar glycerolipids. Infection appears to involve membrane fusion between the virus and host, and we hypothesized that specific polar lipids may facilitate virus attachment. We identified three novel intact polar lipids in E. huxleyi strain CCMP 374 and EhV86, including a GSL with a monosaccharide sialic acid headgroup (sGSL); for all 11 E. huxleyi strains we tested, there was a direct relationship between sGSL content and sensitivity to infection by EhV1, EhV86 and EhV163. In mesocosms, the E. huxleyi population with greatest initial sGSL content had the highest rate of virus-induced mortality. We propose potential physiological roles for sGSL that would be beneficial for growth but leave cells susceptible to infection, thus furthering the discussion of Red Queen-based co-evolution and the cost(s) of sensitivity and resistance in the dynamic E. huxleyi-EhV system., (© 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.)

Pregnant women who present to the emergency department can present challenges that range from the diagnoses of unsuspected pregnancies to the determination of where evaluations should occur. In this review we identify literature associated with the triage of pregnant women in the emergency department and propose a model for triage and evaluation of pregnant women in the emergency department. Strategies are described to facilitate interdepartmental communication to optimize safe maternal/fetal care., (© 2013 AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses.)

Mothers' perceptions of their infants and their own levels of self-efficacy contribute to developing maternal-infant attunement. The purpose of this investigation was to examine the associations between maternal perceptions of their own infants relative to other infants and maternal self-efficacy in a group of ethnically diverse, low-income, first-time mothers during the first six weeks postpartum. By employing a structural equation model approach, we explored relationships between the predictor (maternal neonatal perceptions) and dependent variable (maternal self-efficacy). Changes in maternal perceptions of their own infants significantly contributed to self-reported levels of self-efficacy while controlling for concurrent self-esteem. Maternal perceptions of her infant as less difficult than the average infant at six weeks postpartum predicted increased levels of maternal self-reported self-efficacy. The present study supports further exploration of the first six weeks postpartum as a sensitive period for targeting intervention and support, particularly for mothers and infants at highest risk., (Copyright © 2012 Michigan Association for Infant Mental Health.)

Organic biomarkers in marine sedimentary rocks hold important clues about the early history of Earth's surface environment. The chemical relicts of carotenoids from anoxygenic sulfur bacteria are of particular interest to geoscientists because of their potential to signal episodes of marine photic-zone euxinia such as those proposed for extended periods in the Proterozoic as well as brief intervals during the Phanerozoic. It is therefore critical to constrain the environmental and physiological factors that influence carotenoid production and preservation in modern environments. Here, we present the results of coupled pigment and nucleic acid clone library analyses from planktonic and benthic samples collected from a microbially dominated meromictic lake, Fayetteville Green Lake (New York). Purple sulfur bacteria (PSB) are abundant and diverse both in the water column at the chemocline and in benthic mats below oxygenated shallow waters, with different PSB species inhabiting the two environments. Okenone (from PSB) is an abundant carotenoid in both the chemocline waters and in benthic mats. Green sulfur bacteria and their primary pigment Bchl e are also represented in and below the chemocline. However, the water column and sediments are devoid of the green sulfur bacteria carotenoid isorenieratene. The unexpected absence of isorenieratene and apparent benthic production of okenone provide strong rationale for continued exploration of the microbial ecology of biomarker production in modern euxinic environments., (© 2011 Blackwell Publishing Ltd.)

We describe a trapping and chromatography system that cryogenically removes CO(2) and N(2) generated from sample combustion in an elemental analyzer (EA) and introduces these gases into a low-flow helium carrier stream for isotopic analysis. The sample size required for measurement by this system (termed nano-EA/IRMS) is almost 3 orders of magnitude less than conventional EA analyses and fills an important niche in the range of analytical isotopic methods. Only 25 nmol of N and 41 nmol of C are needed to achieve 1.0 per thousand precision (2sigma) from a single measurement while larger samples and replicate measurements provide better precision. Analyses of standards demonstrate that nano-EA measurements are both accurate and precise, even on nanomolar quantities of C and N. Conventional and nano-EA measurements on international and laboratory standards are indistinguishable within analytical precision. Likewise, nano-EA values for international standards do not differ statistically from their consensus values. Both observations indicate the nano-EA measurements are comparable to conventional EA analyses and accurately reproduce the VPDB and AIR isotopic scales. Critical to the success of the nano-EA system is the procedure for removing the blank contribution to the measured values. Statistical treatment of uncertainties for this procedure yields an accurate method for calculating internal and external precision.

The chronic cranial window preparation allows repeated measurements of the same pial vessels in unanesthetized rats for several weeks and correlation with 24-h monitoring of hemodynamic variables. Nimodipine (20 mg) or placebo was given via two subcutaneous pellets. Large arterioles dilated 26 and 16%, at hour 1 and days 6-13, respectively (P less than 0.02). There was an increase in number of small arterioles throughout the whole observation period with the maximal increment of 47% (P less than 0.05) at days 6-13. Maximal vasodilation with 10% CO2 indicated that the increase in number of small arterioles after administering nimodipine was not caused by the opening of previously closed vessels. The total length of small arterioles and venules increased 47 and 23% at days 6-13, respectively (P less than 0.001). These increases seem to be caused by the increases in the numbers of vessels, because the average length of the small vessels did not appear to change. This suggests that nimodipine reduces cerebral vascular resistance by causing cerebral microvessel neovascularization. Our data demonstrate that the administration of nimodipine (20 mg) is potent in dilating pial arterioles in the short-term without affecting systemic arterial pressure, and that its long-term effect results in new vessel growth.