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As the Medicare Advantage (MA) program grows in enrollment and costs, there has been increasing concern that federal payments to MA plans exceed necessary levels. Estimates suggest that, in 2023, MA plans were paid up to 6% more per enrollee than would have been spent had that beneficiary instead enrolled in traditional Medicare (TM). We evaluated the factors driving this overpayment, characterizing trends in MA benchmarks, bids, and total payments from pre-Affordable Care Act (pre-ACA) levels through 2023. We found that, despite an overall decrease in risk-adjusted bids relative to average risk-adjusted TM enrollee costs, total payments to plans have modestly increased since 2015. Decomposing these trends into various factors in the MA payment formula, we found that divergent trends in benchmarks and bids are, in part, due to the increasing influence of payment adjustments, such as quartile spending adjustments, quality bonus payments, and risk adjustment. Our results suggest that current payment rules have contributed to overpayments and policy reform may be necessary.
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In 2018, the US Congress enacted a policy permitting Medicare Advantage (MA) plans to cover telehealth services in a beneficiary's home and through audio-only means as part of the basic benefit package of services, where prior to the policy change such benefits were only allowed to be covered as a supplemental benefit. MA plans were afforded 2 years of lead time for strategizing, negotiating, and capital investment prior to the start date (January 1, 2020) of the new coverage option. Our data analysis found basic benefit telehealth was offered by plans comprising 71% of enrollment in 2020 and increased to 95% in 2021. At the same time, remote access telehealth was offered as a supplemental benefit for 69% of enrollees in 2020, a decrease of 23% compared to 2019. These efforts by MA plans may have enabled traditional Medicare (TM) to leverage an existing telehealth infrastructure as a solution to the access issues created by public health policies requiring sheltering in place and social distancing during the COVID-19 pandemic. The success of this MA policy prompts consideration of additional flexibility beyond the standard basic benefit package, and whether such benefits reduce costs while improving access and/or outcomes in the context of a managed care environment like MA. Subject to oversight, such flexibility could potentially improve value in MA, and facilitate future changes in TM, as appropriate.
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COVID-19 , Medicare Part C , Telemedicina , Idoso , Estados Unidos , Humanos , Pandemias , Programas de Assistência GerenciadaRESUMO
Gilthead seabream (Sparus aurata) is an important species in Mediterranean aquaculture. Rapid intensification of its production and sub-optimal husbandry practices can cause stress, impairing overall fish performance and raising issues related to sustainability, animal welfare, and food safety. The advent of next-generation sequencing technologies has greatly revolutionized the study of fish stress biology, allowing a deeper understanding of the molecular stress responses. Here, we characterized for the first time, using RNA-seq, the different hepatic transcriptome responses of gilthead seabream to common aquaculture challenges, namely overcrowding, net handling, and hypoxia, further integrating them with the liver proteome and metabolome responses. After reference-guided transcriptome assembly, annotation, and differential gene expression analysis, 7, 343, and 654 genes were differentially expressed (adjusted p-value < 0.01, log2|fold-change| >1) in the fish from the overcrowding, net handling, and hypoxia challenged groups, respectively. Gene set enrichment analysis (FDR < 0.05) suggested a scenario of challenge-specific responses, that is, net handling induced ribosomal assembly stress, whereas hypoxia induced DNA replication stress in gilthead seabream hepatocytes, consistent with proteomics and metabolomics' results. However, both responses converged upon the downregulation of insulin growth factor signalling and induction of endoplasmic reticulum stress. These results demonstrate the high phenotypic plasticity of this species and its differential responses to distinct challenging environments at the transcriptomic level. Furthermore, it provides significant resources for characterizing and identifying potentially novel genes that are important for gilthead seabream resilience and aquaculture production efficiency with regard to fish welfare.
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Dourada , Animais , Dourada/metabolismo , Transcriptoma , RNA-Seq , Multiômica , Perfilação da Expressão Gênica/métodos , Fígado , Aquicultura , HipóxiaAssuntos
Gastos em Saúde , Medicare Part C , Medicare , Transtornos Mentais , Humanos , Estados Unidos , Medicare Part C/economia , Gastos em Saúde/estatística & dados numéricos , Medicare/estatística & dados numéricos , Medicare/economia , Transtornos Mentais/economia , Transtornos Mentais/terapia , Idoso , Estresse FinanceiroRESUMO
With declining biodiversity worldwide, a better understanding of species diversity and their relationships is imperative for conservation and management efforts. Marine sponges are species-rich ecological key players on coral reefs, but their species diversity is still poorly understood. This is particularly true for the demosponge order Haplosclerida, whose systematic relationships are contentious due to the incongruencies between morphological and molecular phylogenetic hypotheses. The single gene markers applied in previous studies did not resolve these discrepancies. Hence, there is a high need for a genome-wide approach to derive a phylogenetically robust classification and understand this group's evolutionary relationships. To this end, we developed a target enrichment-based multilocus probe assay for the order Haplosclerida using transcriptomic data. This probe assay consists of 20,000 enrichment probes targeting 2956 ultraconserved elements in coding (i.e. exon) regions across the genome and was tested on 26 haplosclerid specimens from the Red Sea. Our target-enrichment approach correctly placed our samples in a well-supported phylogeny, in agreement with previous haplosclerid molecular phylogenies. Our results demonstrate the applicability of high-resolution genomic methods in a systematically complex marine invertebrate group and provide a promising approach for robust phylogenies of Haplosclerida. Subsequently, this will lead to biologically unambiguous taxonomic revisions, better interpretations of biological and ecological observations and new avenues for applied research, conservation and managing declining marine diversity.
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Poríferos , Animais , Poríferos/genética , Filogenia , Oceano Índico , Recifes de Corais , BiodiversidadeRESUMO
Beekeeping in Ireland has been strongly impacted by the parasitic mite Varroa destructor, whose introduction caused alarming honeybee colony losses. If unmitigated, these losses could lead to the disappearance of the native honeybee subspecies, Apis mellifera mellifera, with severe consequences for local biodiversity. Although beekeepers play a pivotal role in mitigating this crisis, beekeeping in Ireland is less intensive compared to other European regions, lacking significant infrastructure or support. These circumstances offer a unique opportunity for the development of national programmes that promote sustainable beekeeping practices for varroa control. Notably, local accounts highlight an increasing number of beekeepers successfully managing colonies in the absence of treatments, indicating a potential avenue for developing varroa-resistant stocks through selection of local colonies. Through a survey, we explored beekeeper's opinions and attitudes towards future national projects focused on the development of sustainable beekeeping practices and selection for varroa resistance. The findings confirm the hobbyist nature of Irish beekeepers and their preference for the native honey bee. Some beekeepers were reported to be effectively controlling varroa without treatment, yielding comparable survivals to those using treatments. The majority expressed preference towards a varroa-resistant line if it were of native origin; a few were open to importing non-Irish lines. Overall, a strong willingness to participate in a national breeding programme was expressed. These findings highlight a prime opportunity for Ireland to establish a community-driven strategy based on sustainable beekeeping practices for safeguarding native honeybees and local biodiversity.
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This paper investigates how office-based physicians respond to Medicare reimbursement changes. Using variation from an Affordable Care Act policy that increased reimbursements for office-based care in four states, we use a triple difference analysis, comparing physicians with higher and lower reimbursement changes in treated states to similar physicians in untreated states. We find two mechanisms through which physicians respond. First, the reimbursement change affected integration-physicians with larger increases in office-based reimbursement were less likely to vertically integrate with hospitals and more likely to continue providing office-based care than physicians with smaller reimbursement increases. Second, we find some evidence that physicians who continued practicing in an office setting increased the volume of services provided.
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Medicare , Médicos , Idoso , Estados Unidos , Humanos , Patient Protection and Affordable Care ActRESUMO
AIM: A promising approach for the development of next-generation antimicrobials is to shift their target from causing bacterial death to inhibiting virulence. Marine sponges are an excellent potential source of bioactive anti-virulence molecules (AVM). We screened fractions prepared from 26 samples of Irish coastal sponges for anti-biofilm activity against clinically relevant pathogens. METHODS AND RESULTS: Fifteen fractions from eight sponge species inhibited biofilm of methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), and/or Listeria monocytogenes without causing growth inhibition. Gas chromatograph/mass spectroscopy analyses of Mycale contarenii fractions revealed the presence of myristic acid and oleic acid. These fatty acids repressed transcription of the fibronectin-binding protein fnbA and fnbB genes and the polysaccharide intercellular adhesin icaADBC operon, which are required for MRSA and MSSA biofilm formation, respectively. CONCLUSIONS: This study illustrates the potential of AVM from Irish coastal sponges to specifically target bacterial virulence phenotypes, in this case, repression of biofilm formation via decreased transcription of biofilm-associated genes in MSSA and MRSA.
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Staphylococcus aureus Resistente à Meticilina , Poríferos , Infecções Estafilocócicas , Animais , Resistência a Meticilina , Staphylococcus aureus Resistente à Meticilina/genética , Antibacterianos/farmacologia , Ácidos Graxos/farmacologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus , Biofilmes , Testes de Sensibilidade MicrobianaRESUMO
Insurance markets often feature consumer sorting along both an extensive margin (whether to buy) and an intensive margin (which plan to buy). We present a new graphical theoretical framework that extends a workhorse model to incorporate both selection margins simultaneously. A key insight from our framework is that policies aimed at addressing one margin of selection often involve an economically meaningful trade-off on the other margin in terms of prices, enrollment, and welfare. Using data from Massachusetts, we illustrate these trade-offs in an empirical sufficient statistics approach that is tightly linked to the graphical framework we develop.
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Ascidians or sea squirts are among the marine taxa with the most introduced species worldwide. These animals have a suite of biological characteristics that contribute to their successful establishment, including long reproductive seasons, rapid growth rates, and resistance to pollution. Here, we sequenced a fragment of the 16S ribosomal RNA gene to characterize symbiont diversity and host-specificity in the solitary species Syela clava and Ascidiella aspersa, and the colonial species Didemnum vexillum. Samples were collected from introduced populations in several marinas and mussel facilities around Ireland, and a marina in New Zealand. Two additional colonial species Botrylloides violaceus and Didemnum sp. were collected in Ireland, and ambient seawater was sampled from both countries for comparison. Data revealed a strong effect of host species and location on prokaryote symbiont composition, consistent with recent ascidian microbiome literature. However, a location effect did not manifest in alpha diversity metrics (e.g., the same ascidian species at different locations exhibited similar diversity) but was evident in beta diversity metrics (greater intra-specific differences across locations than within locations). Location effects were stronger than species effects only for the solitary species (i.e., A. aspersa from New Zealand was more similar to S. clava from New Zealand than to A. aspersa from Ireland). D. vexillum and A. aspersa hosted a high abundance of prokaryotic symbionts that were previously found in other ascidian species, while S. clava symbiotic community was more closely related to bacteria common in the marine environment. Further studies should aim to unravel host-microbe coevolutionary patterns and the microbial role in facilitating host establishment in different habitats.
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Microbiota , Urocordados , Animais , Urocordados/microbiologia , Irlanda , Nova Zelândia , Bactérias/genética , Espécies Introduzidas , RNA Ribossômico 16S/genética , FilogeniaRESUMO
Medicare Advantage (MA) plans that bid below benchmarks (or bidding targets) receive a portion of that difference as rebates, which they then must return to beneficiaries through supplemental benefits or reduced premiums or cost-sharing. Using Centers for Medicare & Medicaid Services data, we evaluate the growth in rebates and concomitant changes in supplemental benefit composition among health maintenance organizations (HMOs) and local preferred provider organizations (PPOs) from 2011 through 2022. Average rebates grew considerably, particularly after 2015 and among PPOs. Alongside this rebate growth, the share of enrollees in plans offering dental, vision, and hearing benefits also increased, with nearly universal coverage of these benefits among both HMOs and PPOs by 2022. Medicare Advantage plans also increasingly reduced beneficiary Part D premium obligations, while increasing beneficiary financial exposure in the form of higher Part D deductibles, medical out-of-pocket maximums, and cost-sharing for inpatient stays. These findings are particularly relevant as policymakers debate the merits of various reforms to MA payment policy.
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Amoebic gill disease (AGD) and complex gill disease (CGD) are recurrent gill disorders in Atlantic salmon, resulting in significant aquaculture losses. The role of gill microbiomes in gill disease development is unclear. We undertook a longitudinal study to characterise the gill tissue and gill mucus microbiomes of farmed Atlantic salmon before, and during, a gill disease episode. Using a newly optimised DNA extraction protocol, we sequenced rRNA genes from microbiomes of gill samples taken from 105 individual salmon on a farm, over a summer season. The AGD aetiological agent, Neoparamoeba perurans, was PCR-quantified targeting 18S rRNA genes. Similar analyses were carried out on mucus samples. Mucus scrapings were suitable, non-lethal substitutes for characterisation of the gill prokaryotic community in this study. Gill tissue and gill mucus microbiomes changed during the campaign, correlating with N. perurans concentrations. Time explained 35% of the gill tissue and gill mucus microbiome variance, while N. perurans concentrations explained 5%. Genera including Dyadobacter, Shewanella and Pedobacter were maximally abundant in gill and mucus samples at the timepoint prior to the the detection of gill disorder signs, at T3. Shewanella was significantly more abundant before than during the gill disease episode, and we suggest this genus could be considered in future studies addressing relationships between gill disease and the gill microbiome.
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Doenças dos Peixes , Microbiota , Salmo salar , Amebíase , Animais , DNA , Doenças dos Peixes/diagnóstico , Brânquias , Estudos Longitudinais , MucoRESUMO
Importance: Medicaid is an important source of supplemental coverage for older Medicare beneficiaries with low income. Research has shown that Medicaid expansion under the Patient Protection and Affordable Care Act (ACA) was associated with increased Medicaid coverage for previously eligible older adults with low income, but there has been little research on whether their health care use increased or whether such changes differed by beneficiaries' health status. Objective: To assess whether the ACA Medicaid expansion to working-age adults was associated with increased Medicaid enrollment and health care use among older adults with low income with and without chronic condition limitations. Design Setting and Participants: This cross-sectional study used data from the National Health Interview Survey from 2010 to 2017 for adults 65 years or older with low income (≤100% of the federal poverty level). Data were analyzed from November 2020 to March 2022. Exposure: Residence in a state with Medicaid expansion for working-age adults. Main Outcomes and Measures: The main outcomes were Medicaid coverage and health care use, measured by physician office visits and inpatient hospital care. Survey weights were used in calculating descriptive statistics and regression estimates. In multivariate analysis, difference-in-differences models were used to compare changes in outcomes over time between respondents in Medicaid expansion states and respondents in nonexpansion states. Results: Of 21 859 adults included in the study, 7153 had chronic condition limitations (4983 [70.1%] female; mean [SD] age, 76.0 [0.1] years) and 14 706 did not have chronic condition limitations (9609 [66.3%] female; mean [SD] age, 74.85 [0.08] years). Of those with chronic condition limitations, 2707 (36.7%) were enrolled in Medicaid, 2816 (39.4%) had an office visit in the past 2 weeks, and 2152 (30.7%) used inpatient hospital care in the past year. Medicaid expansion was associated with differential increases in the likelihood of having Medicaid (4.92 percentage points; 95% CI, 0.25-9.60 percentage points; P = .04) and having an office visit in the past 2 weeks (5.31 percentage points; 95% CI, 0.10-10.51 percentage points; P = .046) compared with nonexpansion. There were no differential changes between expansion and nonexpansion states in receipt of inpatient hospital care (-0.62 percentage points; 95% CI, -5.39 to 4.14 percentage points; P = .79). Among adults without chronic condition limitations, 3159 (19.8%) were enrolled in Medicaid, and no differential changes between expansion and nonexpansion states in Medicaid enrollment (-0.24 percentage points; 95% CI, -3.06 to 2.57 percentage points; P = .86) or health care use were found. Conclusions and Relevance: In this cross-sectional study, ACA Medicaid expansion for working-age adults was associated with increased Medicaid enrollment and outpatient health care use among older adults with low income and chronic condition limitations who were dually eligible for Medicare and Medicaid.
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Medicaid , Patient Protection and Affordable Care Act , Idoso , Doença Crônica , Estudos Transversais , Atenção à Saúde , Feminino , Humanos , Cobertura do Seguro , Masculino , Medicare , Pobreza , Estados UnidosRESUMO
Actinoporins are proteinaceous toxins known for their ability to bind to and create pores in cellular membranes. This quality has generated interest in their potential use as new tools, such as therapeutic immunotoxins. Isolated historically from sea anemones, genes encoding for similar actinoporin-like proteins have since been found in a small number of other animal phyla. Sequencing and de novo assembly of Irish Haliclona transcriptomes indicated that sponges also possess similar genes. An exhaustive analysis of publicly available sequencing data from other sponges showed that this is a potentially widespread feature of the Porifera. While many sponge proteins possess a sequence similarity of 27.70-59.06% to actinoporins, they show consistency in predicted structure. One gene copy from H. indistincta has significant sequence similarity to sea anemone actinoporins and possesses conserved residues associated with the fundamental roles of sphingomyelin recognition, membrane attachment, oligomerization, and pore formation, indicating that it may be an actinoporin. Phylogenetic analyses indicate frequent gene duplication, no distinct clade for sponge-derived proteins, and a stronger signal towards actinoporins than similar proteins from other phyla. Overall, this study provides evidence that a diverse array of Porifera represents a novel source of actinoporin-like proteins which may have biotechnological and pharmaceutical applications.
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Organismos Aquáticos/química , Produtos Biológicos/química , Poríferos/química , Animais , FilogeniaRESUMO
During the COVID-19 pandemic in the US, essential workers have provided health care, food, and other necessities, often incurring considerable risk. At the pandemic's start, the federal government was in the process of tightening the "public charge" rule by adding nutrition and health benefits to the cash benefits that, if drawn, could subject immigrants to sanctions (for example, green card denial). Census Bureau data indicate that immigrants accounted for 13.6 percent of the population but 17.8 percent of essential workers in 2019. About 20.0 million immigrants held essential jobs, and more than one-third of these immigrants resided in US states bordering Mexico. Nationwide, 12.3 million essential workers and 18.9 million of their household members were at risk because of the new sanctions. The rule change (which was subsequently revoked) likely caused 2.1 million essential workers and household members to forgo Medicaid and 1.3 million to forgo Supplemental Nutrition Assistance Program assistance on the eve of the pandemic, highlighting the potential of immigration policy changes to exacerbate health risks.
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COVID-19 , Emigrantes e Imigrantes , Assistência Alimentar , Humanos , Medicaid , México , Pandemias , SARS-CoV-2 , Estados UnidosRESUMO
The first taxonomic descriptions of the sponge diversity at El Pelado Marine Protected Area in the province of Santa Elena, Ecuador is reported. Tedania (Tedania) ecuadoriensis Jaramillo & Hajdu, sp. nov. is described from its shallow waters. In addition, Callyspongia (Callyspongia) aff. californica (sensuCruz-Barraza and Carballo 2008; non sensuDickinson 1945) and Cliona aff. euryphylle are reported for the first time. The former species is likely distributed over 4,000 km along the Tropical Eastern Pacific, whereas the latter might be an example of a trans-isthmian lineage. An amended diagnosis for Callyspongia (Callyspongia) and an updated identification key for the subgenera of Callyspongia are provided.
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Betacoronavirus , Infecções por Coronavirus/transmissão , Características da Família , Renda , Doenças Profissionais/etiologia , Pneumonia Viral/transmissão , Recursos Humanos/economia , Negro ou Afro-Americano/estatística & dados numéricos , Idoso/estatística & dados numéricos , COVID-19 , Censos , Infecções por Coronavirus/epidemiologia , Feminino , Mão de Obra em Saúde/classificação , Mão de Obra em Saúde/economia , Mão de Obra em Saúde/estatística & dados numéricos , Hispânico ou Latino/estatística & dados numéricos , Humanos , Renda/classificação , Renda/estatística & dados numéricos , Indústrias/classificação , Indústrias/estatística & dados numéricos , Masculino , Pessoas sem Cobertura de Seguro de Saúde/estatística & dados numéricos , Doenças Profissionais/epidemiologia , Ocupações/classificação , Ocupações/estatística & dados numéricos , Pandemias , Pneumonia Viral/epidemiologia , Saúde Pública , Medição de Risco/economia , Medição de Risco/estatística & dados numéricos , SARS-CoV-2 , Distribuição por Sexo , Estados Unidos/epidemiologia , Recursos Humanos/classificação , Recursos Humanos/estatística & dados numéricosRESUMO
The emergence of antibiotic resistance and viruses with high epidemic potential made unexplored marine environments an appealing target source for new metabolites. Marine fungi represent one of the most suitable sources for the discovery of new compounds. Thus, the aim of this work was (i) to isolate and identify fungi associated with the Atlantic sponge Grantia compressa; (ii) to study the fungal metabolites by applying the OSMAC approach (one strain; many compounds); (iii) to test fungal compounds for their antimicrobial activities. Twenty-one fungal strains (17 taxa) were isolated from G. compressa. The OSMAC approach revealed an astonishing metabolic diversity in the marine fungus Eurotium chevalieri MUT 2316, from which 10 compounds were extracted, isolated, and characterized. All metabolites were tested against viruses and bacteria (reference and multidrug-resistant strains). Dihydroauroglaucin completely inhibited the replication of influenza A virus; as for herpes simplex virus 1, total inhibition of replication was observed for both physcion and neoechinulin D. Six out of 10 compounds were active against Gram-positive bacteria with isodihydroauroglaucin being the most promising compound (minimal inhibitory concentration (MIC) 4-64 µg/mL) with bactericidal activity. Overall, G. compressa proved to be an outstanding source of fungal diversity. Marine fungi were capable of producing different metabolites; in particular, the compounds isolated from E. chevalieri showed promising bioactivity against well-known and emerging pathogens.
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Antibacterianos/farmacologia , Antivirais/farmacologia , Biotecnologia/métodos , Eurotium/metabolismo , Poríferos/microbiologia , Animais , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antivirais/química , Antivirais/isolamento & purificação , Organismos Aquáticos/genética , Organismos Aquáticos/isolamento & purificação , Organismos Aquáticos/metabolismo , Biodiversidade , Chlorocebus aethiops , Cães , Eurotium/genética , Eurotium/isolamento & purificação , Bactérias Gram-Positivas/efeitos dos fármacos , Herpesvirus Humano 1/efeitos dos fármacos , Vírus da Influenza A/efeitos dos fármacos , Células Madin Darby de Rim Canino , Testes de Sensibilidade Microbiana , Células Vero , Replicação Viral/efeitos dos fármacosRESUMO
Silicatein is the main protein responsible for the formation of spicules, tiny structures that constitute the silica skeleton of marine demosponges (Phylum Porifera). A unique innovation in Porifera that evolved from the cathepsin L family of proteins, it has been reported that two amino acids (S and H) are necessary to form the catalytic triad (SHN) to enable silica condensation. However, a diversity of silicatein sequence variants has since been reported with a variable pattern of presence/absence across sponge groups. Variants containing CHN or C/SQN at the active site appear more common in sponges from the Haplosclerida. Here, we report the expression levels of five silicatein variants through different developmental stages in the haplosclerid Haliclona indistincta. All five silicatein variants were expressed at low levels in the free-swimming larvae, which lack spicules and expression significantly increased at the two developmental phases in which spicules were visible. At these two phases, silicateins of CHN and C/SQN types were much more highly expressed than the SHN type indicating a possible ability of active sites with these alternative amino acids to condense silica and a more complex evolutionary story for spicule formation in marine demosponges than previously understood.
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Catepsinas/genética , Regulação da Expressão Gênica no Desenvolvimento , Haliclona/genética , Animais , Catepsinas/química , Catepsinas/metabolismo , Haliclona/crescimento & desenvolvimento , Haliclona/metabolismoRESUMO
MAIN CONCLUSION: A cell death signal is perceived and responded to by epidermal cells first before being conveyed inwards across the anther wall in male sterile Plantago lanceolata flowers. In gynodioecious plants, floral phenotype is determined by an interplay between cytoplasmic male sterility (CMS)-promoting factors and fertility-restoring genes segregating in the nuclear background. Plantago lanceolata exhibits at least four different sterilizing cytoplasms. MS1, a "brown-anther" male sterile phenotype, segregates with a CMSI cytoplasm and a non-restoring nuclear background in P. lanceolata populations. The aim of this study was to investigate the cytology of early anther development in segregating hermaphrodite and male sterile flowers sharing the same CMSI cytoplasm, and to determine if the sterility phenotype correlates with any changes to the normal pattern of programmed cell death (PCD) that occurs during anther development. Cytology shows cellular abnormalities in all four anther wall layers (epidermis, endothecium, middle layer and tapetum), the persistence and enlargement of middle layer and tapetal cells, and the failure of microspore mother cells to complete meiosis in male sterile anthers. In these anthers, apoptotic-PCD occurs earlier than in fertile anthers and is detected in all four cell layers of the anther wall before the middle layer and tapetal cells become enlarged. PCD is separated spatially and temporally within the anther wall, occurring first in epidermal cells before extending radially to cells in the inner anther wall layers. This is the first evidence of a cell death signal being perceived and responded to by epidermal cells first before being conveyed inwards across the anther wall in male sterile plants.