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1.
Circulation ; 2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33648345

RESUMO

Background: Human engineered heart tissue (EHT) transplantation represents a potential regenerative strategy for heart failure patients and has been successful in preclinical models. Clinical application requires upscaling, adaptation to good manufacturing practices (GMP) and determination of the effective dose. Methods: Cardiomyocytes were differentiated from three different human induced pluripotent stem cell (hiPSC) lines including one reprogrammed under GMP conditions. Protocols for hiPSC expansion, cardiomyocyte differentiation and EHT generation were adapted to substances available in GMP quality. EHT geometry was modified to generate patches suitable for transplantation in a small animal model and perspectively humans. Repair efficacy was evaluated at 3 doses in a cryo-injury guinea pig model. Human-scale patches were epicardially transplanted onto healthy hearts in pigs to assess technical feasibility. Results: We created mesh structured tissue patches for transplantation in guinea pigs (1.5x2.5 cm, 9-15x106 cardiomyocytes) and pigs (5x7 cm, 450 x106 cardiomyocytes). EHT patches coherently beat in culture and developed high force (mean 4.6 mN). Cardiomyocytes matured, aligned along the force lines, and demonstrated advanced sarcomeric structure and action potential characteristics closely resembling human ventricular tissue. EHT patches containing ~4.5, 8.5, 12x106 or no cells were transplanted 7 days after cryo-injury (n=18-19 per group). EHT transplantation resulted in a dose-dependent remuscularization (graft size: 0-12% of the scar). Only high-dose patches improved left-ventricular function (+8% absolute, +24% relative increase). The grafts showed time-dependent cardiomyocyte proliferation. While standard EHT patches did not withstand transplantation in pigs, the human-scale patch enabled successful patch transplantation. Conclusions: EHT patch transplantation resulted in a partial remuscularization of the injured heart and improved left-ventricular function in a dose-dependent manner in a guinea pig injury model. Human scale patches were successfully transplanted in pigs in a proof-of-principle study.

2.
ISME J ; 2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33479490

RESUMO

Invasive species are co-introduced with microbiota from their native range and also interact with microbiota found in the novel environment to which they are introduced. Host flexibility toward microbiota, or host promiscuity, is an important trait underlying terrestrial plant invasions. To test whether host promiscuity may be important in macroalgal invasions, we experimentally simulated an invasion in a common garden setting, using the widespread invasive macroalga Agarophyton vermiculophyllum as a model invasive seaweed holobiont. After disturbing the microbiota of individuals from native and non-native populations with antibiotics, we monitored the microbial succession trajectories in the presence of a new source of microbes. Microbial communities were strongly impacted by the treatment and changed compositionally and in terms of diversity but recovered functionally by the end of the experiment in most respects. Beta-diversity in disturbed holobionts strongly decreased, indicating that different populations configure more similar -or more common- microbial communities when exposed to the same conditions. This decline in beta-diversity occurred not only more rapidly, but was also more pronounced in non-native populations, while individuals from native populations retained communities more similar to those observed in the field. This study demonstrates that microbial communities of non-native A. vermiculophyllum are more flexibly adjusted to the environment and suggests that an intraspecific increase in host promiscuity has promoted the invasion process of A. vermiculophyllum. This phenomenon may be important among invasive macroalgal holobionts in general.

3.
Microorganisms ; 8(12)2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-33265911

RESUMO

Terrestrial plants are known to "garden" the microbiota of their rhizosphere via released metabolites (that can attract beneficial microbes and deter pathogenic microbes). Such a "gardening" capacity is also known to be dynamic in plants. Although microbial "gardening" has been recently demonstrated for seaweeds, we do not know whether this capacity is a dynamic property in any aquatic flora like in terrestrial plants. Here, we tested the dynamic microbial "gardening" capacity of seaweeds using the model invasive red seaweed Agarophyton vermiculophyllum. Following an initial extraction of surface-associated metabolites (immediately after field collection), we conducted a long-term mesocosm experiment for 5 months to test the effect of two different salinities (low = 8.5 and medium = 16.5) on the microbial "gardening" capacity of the alga over time. We tested "gardening" capacity of A. vermiculophyllum originating from two different salinity levels (after 5 months treatments) in settlement assays against three disease causing pathogenic bacteria and seven protective bacteria. We also compared the capacity of the alga with field-collected samples. Abiotic factors like low salinity significantly increased the capacity of the alga to deter colonization by pathogenic bacteria while medium salinity significantly decreased the capacity of the alga over time when compared to field-collected samples. However, capacity to attract beneficial bacteria significantly decreased at both tested salinity levels when compared to field-collected samples. Dynamic microbial "gardening" capacity of a seaweed to attract beneficial bacteria and deter pathogenic bacteria is demonstrated for the first time. Such a dynamic capacity as found in the current study could also be applicable to other aquatic host-microbe interactions. Our results may provide an attractive direction of research towards manipulation of salinity and other abiotic factors leading to better defended A. vermiculophyllum towards pathogenic bacteria thereby enhancing sustained production of healthy A. vermiculophyllum in farms.

4.
Annu Rev Physiol ; 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-33064963

RESUMO

The regenerative capacity of the heart has long fascinated scientists. In contrast to other organs such as liver, skin, and skeletal muscle, the heart possesses only a minimal regenerative capacity. It lacks a progenitor cell population, and cardiomyocytes exit the cell cycle shortly after birth and do not re-enter after injury. Thus, any loss of cardiomyocytes is essentially irreversible and can lead to or exaggerate heart failure, which represents a major public health problem. New therapeutic options are urgently needed, but regenerative therapies have remained an unfulfilled promise in cardiovascular medicine until today. Yet, through a clearer comprehension of signaling pathways that regulate the cardiomyocyte cell cycle and advances in stem cell technology, strategies have evolved that demonstrate the potential to generate new myocytes and thereby fulfill an essential central criterion for heart repair. Expected final online publication date for the Annual Review of Physiology, Volume 83 is February 10, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

5.
Curr Protoc Stem Cell Biol ; 55(1): e127, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32956561

RESUMO

The reproducibility of stem cell research relies on the constant availability of quality-controlled cells. As the quality of human induced pluripotent stem cells (hiPSCs) can deteriorate in the course of a few passages, cell banking is key to achieve consistent results and low batch-to-batch variation. Here, we provide a cost-efficient route to generate master and working cell banks for basic research projects. In addition, we describe minimal protocols for quality assurance including tests for sterility, viability, pluripotency, and genetic integrity. © 2020 The Authors. Basic Protocol 1: Expansion of hiPSCs Basic Protocol 2: Cell banking of hiPSCs Support Protocol 1: Pluripotency assessment by flow cytometry Support Protocol 2: Thawing control: Viability and sterility Support Protocol 3: Potency, viral clearance, and pluripotency: Spontaneous differentiation and qRT-PCR Support Protocol 4: Identity: Short tandem repeat analysis.

6.
Clin Ther ; 42(10): 1892-1910, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32938533

RESUMO

PURPOSE: Adverse cardiovascular drug effects pose a substantial medical risk and represent a common cause of drug withdrawal from the market. Thus, current in vitro assays and in vivo animal models still have shortcomings in assessing cardiotoxicity. A human model for more accurate preclinical cardiotoxicity assessment is highly desirable. Current differentiation protocols allow for the generation of human pluripotent stem cell-derived cardiomyocytes in basically unlimited numbers and offer the opportunity to study drug effects on human cardiomyocytes. The purpose of this review is to provide a brief overview of the current approaches to translate studies with pluripotent stem cell-derived cardiomyocytes from basic science to preclinical risk assessment. METHODS: A review of the literature was performed to gather data on the pathophysiology of cardiotoxicity, the current cardiotoxicity screening assays, stem cell-derived cardiomyocytes, and their application in cardiotoxicity screening. FINDINGS: There is increasing evidence that stem cell-derived cardiomyocytes predict arrhythmogenicity with high accuracy. Cardiomyocyte immaturity represents the major limitation so far. However, strategies are being developed to overcome this hurdle, such as tissue engineering. In addition, stem cell-based strategies offer the possibility to assess structural drug toxicity (eg, by anticancer drugs) on complex models that more closely mirror the structure of the heart and contain endothelial cells and fibroblasts. IMPLICATIONS: Pluripotent stem cell-derived cardiomyocytes have the potential to substantially change how preclinical cardiotoxicity screening is performed. To which extent they will replace or complement current approaches is being evaluated.

7.
Int J Syst Evol Microbiol ; 70(7): 4305-4314, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32579104

RESUMO

A new member of the family Flavobacteriaceae was isolated from the biofilm of a stone at Nordstrand, a peninsula at the German North Sea shore. Phylogenetic analysis of the 16S rRNA gene sequence showed that strain ANORD1T was most closely related to the validly described type strains Polaribacter porphyrae LNM-20T (97.0 %) and Polaribacter reichenbachii KMM 6386T (96.9 % 16S rRNA gene sequence similarity) and clustered with Polaribacter gangjinensis K17-16T (96.0 %). Strain ANORD1T was determined to be mesophilic, Gram-negative, non-motile and strictly aerobic. Optimal growth was observed at 20-30 °C, within a salinity range of 2-7 % sea salt and from pH 7-10. Like other type strains of the genus Polaribacter, ANORD1T was tested negative for flexirubin-type pigments, while carotenoid-type pigments were detected. The DNA G+C content of strain ANORD1T was 30.6 mol%. The sole respiratory quinone detected was menaquinone 6 (MK-6). The major fatty acids identified were C15 : 0, iso-C15 : 0, C15 : 1 ω6c and iso-C15 : 0 3-OH. Based on the polyphasic approach, strain ANORD1T represents a novel species in the genus Polaribacter, with the name Polaribacter septentrionalilitoris sp. nov. being proposed. The type strain is ANORD1T (=DSM 110039T=NCIMB 15081T=MTCC 12685T).


Assuntos
Biofilmes , Flavobacteriaceae/classificação , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , Carotenoides/química , DNA Bacteriano/genética , Ácidos Graxos/química , Flavobacteriaceae/isolamento & purificação , Mar do Norte , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
8.
Mol Ecol ; 29(11): 2094-2108, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32408381

RESUMO

Communities are shaped by scale dependent processes. To study the diversity and variation of microbial communities across scales, the invasive and widespread seaweed Agarophyton vermiculophyllum presents a unique opportunity. We characterized pro- and eukaryotic communities associated with this holobiont across its known distribution range, which stretches over the northern hemisphere. Our data reveal that community composition and diversity in the holobiont vary at local but also larger geographic scales. While processes acting at the local scale (i.e., within population) are the main structuring drivers of associated microbial communities, changes in community composition also depend on processes acting at larger geographic scales. Interestingly, the largest analysed scale (i.e., native and non-native ranges) explained variation in the prevalence of predicted functional groups, which could suggest a functional shift in microbiota occurred over the course of the invasion process. While high variability in microbiota at the local scale supports A. vermiculophyllum to be a generalist host, we also identified a number of core taxa. These geographically independent holobiont members imply that cointroduction of specific microbiota may have additionally promoted the invasion process.

9.
Cardiovasc Res ; 2020 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-32365197

RESUMO

Echocardiography is a reliable and reproducible method to assess non-invasively cardiac function in clinical and experimental research. Significant progress in the development of echocardiographic equipment and transducers has led to the successful translation of this methodology from humans to rodents, allowing for the scoring of disease severity and progression, testing of new drugs, and monitoring cardiac function in genetically modified or pharmacologically treated animals. However, as yet, there is no standardization in the procedure to acquire echocardiographic measurements in small animals. This position paper focuses on the appropriate acquisition and analysis of echocardiographic parameters in adult mice and rats, and provides reference values, representative images and videos for the accurate and reproducible quantification of left ventricular function in healthy and pathological conditions.

10.
Glob Chang Biol ; 26(2): 417-430, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31670451

RESUMO

Marine heatwaves have been observed worldwide and are expected to increase in both frequency and intensity due to climate change. Such events may cause ecosystem reconfigurations arising from species range contraction or redistribution, with ecological, economic and social implications. Macrophytes such as the brown seaweed Fucus vesiculosus and the seagrass Zostera marina are foundation species in many coastal ecosystems of the temperate northern hemisphere. Hence, their response to extreme events can potentially determine the fate of associated ecosystems. Macrophyte functioning is intimately linked to the maintenance of photosynthesis, growth and reproduction, and resistance against pathogens, epibionts and grazers. We investigated morphological, physiological, pathological and chemical defence responses of western Baltic Sea F. vesiculosus and Z. marina populations to simulated near-natural marine heatwaves. Along with (a) the control, which constituted no heatwave but natural stochastic temperature variability (0HW), two treatments were applied: (b) two late-spring heatwaves (June, July) followed by a summer heatwave (August; 3HW) and (c) a summer heatwave only (1HW). The 3HW treatment was applied to test whether preconditioning events can modulate the potential sensitivity to the summer heatwave. Despite the variety of responses measured in both species, only Z. marina growth was impaired by the accumulative heat stress imposed by the 3HW treatment. Photosynthetic rate, however, remained high after the last heatwave indicating potential for recovery. Only epibacterial abundance was significantly affected in F. vesiculosus. Hence both macrophytes, and in particular F. vesiculosus, seem to be fairly tolerant to short-term marine heatwaves at least at the intensities applied in this experiment (up to 5°C above mean temperature over a period of 9 days). This may partly be due to the fact that F. vesiculosus grows in a highly variable environment, and may have a high phenotypic plasticity.


Assuntos
Fucus , Zosteraceae , Mudança Climática , Ecossistema , Temperatura
11.
Nat Biotechnol ; 37(8): 895-906, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31375810

RESUMO

The epicardium and its derivatives provide trophic and structural support for the developing and adult heart. Here we tested the ability of human embryonic stem cell (hESC)-derived epicardium to augment the structure and function of engineered heart tissue in vitro and to improve efficacy of hESC-cardiomyocyte grafts in infarcted athymic rat hearts. Epicardial cells markedly enhanced the contractility, myofibril structure and calcium handling of human engineered heart tissues, while reducing passive stiffness compared with mesenchymal stromal cells. Transplanted epicardial cells formed persistent fibroblast grafts in infarcted hearts. Cotransplantation of hESC-derived epicardial cells and cardiomyocytes doubled graft cardiomyocyte proliferation rates in vivo, resulting in 2.6-fold greater cardiac graft size and simultaneously augmenting graft and host vascularization. Notably, cotransplantation improved systolic function compared with hearts receiving either cardiomyocytes alone, epicardial cells alone or vehicle. The ability of epicardial cells to enhance cardiac graft size and function makes them a promising adjuvant therapeutic for cardiac repair.


Assuntos
Coração/fisiologia , Células-Tronco Embrionárias Humanas , Infarto do Miocárdio/terapia , Miócitos Cardíacos , Regeneração , Animais , Embrião de Galinha , Regulação da Expressão Gênica , Humanos , Masculino , Ratos , Ratos Nus , Ratos Sprague-Dawley , Engenharia Tecidual
12.
Ecol Evol ; 9(16): 9225-9238, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31463018

RESUMO

In the course of the ongoing global intensification and diversification of human pressures, the study of variation patterns of biological traits along environmental gradients can provide relevant information on the performance of species under shifting conditions. The pronounced salinity gradient, co-occurrence of multiple stressors, and accelerated rates of change make the Baltic Sea and its transition to North Sea a suitable region for this type of study. Focusing on the bladderwrack Fucus vesiculosus, one of the main foundation species on hard-bottoms of the Baltic Sea, we analyzed the phenotypic variation among populations occurring along 2,000 km of coasts subjected to salinities from 4 to >30 and a variety of other stressors. Morphological and biochemical traits, including palatability for grazers, were recorded at 20 stations along the Baltic Sea and four stations in the North Sea. We evaluated in a common modeling framework the relative contribution of multiple environmental drivers to the observed trait patterns. Salinity was the main and, in some cases, the only environmental driver of the geographic trait variation in F. vesiculosus. The decrease in salinity from North Sea to Baltic Sea stations was accompanied by a decline in thallus size, photosynthetic pigments, and energy storage compounds, and affected the interaction of the alga with herbivores and epibiota. For some traits, drivers that vary locally such as wave exposure, light availability or nutrient enrichment were also important. The strong genetic population structure in this macroalgae might play a role in the generation and maintenance of phenotypic patterns across geographic scales. In light of our results, the desalination process projected for the Baltic Sea could have detrimental impacts on F. vesiculosus in areas close to its tolerance limit, affecting ecosystem functions such as habitat formation, primary production, and food supply.

13.
Sci Rep ; 9(1): 9831, 2019 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-31285568

RESUMO

Human iPSC-derived engineered heart tissue (hEHT) has been used to remuscularize injured hearts in a guinea pig infarction model. While beneficial effects on cardiac remodeling have been demonstrated, the arrhythmogenic potential of hEHTs is a major concern. We investigated whether hiPSC-derived hEHTs increase the incidence of ventricular arrhythmias. HEHTs were created from human iPSC-derived cardiomyocytes and endothelial cells. Left-ventricular cryo-injury was induced in guinea pigs (n = 37) and telemetry sensors for continuous ECG monitoring were implanted. 7 days following the cryo-injury, hEHTs or cell-free constructs were transplanted into the surviving animals (n = 15 and n = 9). ECGs were recorded over the following 28 days. 10 hEHT animals and 8 control animals survived the observation period and were included in the final analysis. After implantation of hEHTs or cell-free constructs, ventricular arrhythmias (premature ventricular contractions, couplets, triplets and non-sustained ventricular tachycardia) were observed in animals of both groups. The fraction of animals with the respective arrhythmias as well as the rate of arrhythmic events did not differ between groups. Following hEHT implantation, no clinically relevant sustained ventricular tachycardia or ventricular fibrillation was detected. Our telemetric data provides first evidence for the electrical safety of human iPSC-derived EHTs in this experimental model, thereby supporting further development of this approach.


Assuntos
Arritmias Cardíacas/diagnóstico , Congelamento/efeitos adversos , Células-Tronco Pluripotentes Induzidas/citologia , Infarto do Miocárdio/terapia , Miócitos Cardíacos/transplante , Animais , Diferenciação Celular , Modelos Animais de Doenças , Eletrocardiografia , Cobaias , Humanos , Infarto do Miocárdio/complicações , Infarto do Miocárdio/etiologia , Miócitos Cardíacos/citologia , Telemetria , Engenharia Tecidual
14.
J Vis Exp ; (145)2019 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-30933073

RESUMO

Due to the limited regeneration capacity of the heart in adult mammals, myocardial infarction results in an irreversible loss of cardiomyocytes. This loss of relevant amounts of heart muscle mass can lead to the heart failure. Besides heart transplantation, there is no curative treatment option for the end-stage heart failure. In times of organ donor shortage, organ independent treatment modalities are needed. Left-ventricular assist devices are a promising therapy option, however, especially as destination therapy, limited by its side-effects like stroke, infections and bleedings. In recent years, several cardiac repair strategies including stem cell injection, cardiac progenitors or myocardial tissue engineering have been investigated. Recent improvements in cell biology allow for the differentiation of large amounts of cardiomyocytes derived from human induced pluripotent stem cells (iPSC). One of the cardiac repair strategies currently under evaluation is to transplant artificial heart tissue. Engineered heart tissue (EHT) is a three-dimensional in vitro created cardiomyocyte network, with functional properties of native heart tissue. We have created EHT-patches from hiPSC derived cardiomyocytes. Here we present a protocol for the induction of left ventricular myocardial cryoinjury in a guinea pig, followed by implantation of hiPSC derived EHT on the left ventricular wall.


Assuntos
Implantes Experimentais , Células-Tronco Pluripotentes Induzidas/citologia , Miocárdio/patologia , Implantação de Prótese , Animais , Modelos Animais de Doenças , Feminino , Cobaias , Ventrículos do Coração/diagnóstico por imagem , Ventrículos do Coração/patologia , Humanos , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/patologia
16.
Sci Rep ; 9(1): 3323, 2019 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-30804483

RESUMO

Plants rely on both mechanical and chemical defence mechanisms to protect their surfaces against microorganisms. The recently completed genome of the eelgrass Zostera marina, a marine angiosperm with fundamental importance for coastal ecosystems, showed that its re-adaptation from land to the sea has led to the loss of essential genes (for chemical communication and defence) and structural features (stomata and thick cuticle) that are typical of terrestrial plants. This study was designed to understand the molecular nature of surface protection and fouling-control strategy of eelgrass against marine epiphytic yeasts. Different surface extraction methods and comparative metabolomics by tandem mass spectrometry (LC-MS/MS) were used for targeted and untargeted identification of the metabolite profiles of the leaf surface and the whole tissue extracts. Desorption electrospray ionization-imaging mass spectrometry (DESI-IMS) coupled with traditional bioassays revealed, for the first time, the unique spatial distribution of the eelgrass surface-associated phenolics and fatty acids, as well as their differential bioactivity against the growth and settlement of epiphytic yeasts. This study provides insights into the complex chemical defence system of the eelgrass leaf surface. It suggests that surface-associated metabolites modulate biotic interactions and provide chemical defence and structural protection to eelgrass in its marine environment.


Assuntos
Folhas de Planta/microbiologia , Folhas de Planta/fisiologia , Zosteraceae/microbiologia , Zosteraceae/fisiologia , Aclimatação/fisiologia , Cromatografia Líquida/métodos , Ecossistema , Folhas de Planta/metabolismo , Água do Mar/microbiologia , Espectrometria de Massas em Tandem/métodos , Zosteraceae/metabolismo
17.
Front Microbiol ; 10: 2870, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-32010064

RESUMO

The establishment of epibacterial communities is fundamental to seaweed health and fitness, in modulating ecological interactions and may also facilitate adaptation to new environments. Abiotic factors like salinity can determine bacterial abundance, growth and community composition. However, influence of salinity as a driver of epibacterial community composition (until species level) has not been investigated for seaweeds and especially under long time scales. We also do not know how abiotic stressors may influence the 'core' bacterial species of seaweeds. Following an initial (immediately after field collection) sampling of epibacterial community of an invasive red seaweed Agarophyton vermicullophylum, we conducted a long term mesocosm experiment for 5 months, to examine the influence of three different salinities (low, medium and high) at two different time points (3 months after start of experiment and 5 months, i.e., at the end of experiment) on the epibacterial community richness and composition of Agarophyton. Metagenomic sequencing showed that epibacterial communities changed significantly according to salinity and time points sampled. Epibacterial richness was significantly different between low and high salinities at both time points. Epibacterial richness also varied significantly between 3 months (after start of experiment) and 5 months (end of experiment) within low, medium and high salinity level. Irrespective of salinity levels and time points sampled 727 taxa consistently appeared in all Agarophyton samples hinting at the presence of core bacterial species on the surface of the alga. Our results indicate that both salinity and time can be major driving forces in structuring epibacterial communities of seaweeds with respect to richness and ß-diversity. We highlight the necessity of conducting long term experiments allowing us to detect and understand epibacterial succession over time on seaweeds.

18.
J Phycol ; 55(1): 25-36, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30367499

RESUMO

As one of the most abundant and ubiquitous representatives of marine and brackish coastal macrophytobenthos communities, the genus Ulva is not only an important primary producer but also of ecological and morphogenetic interest to many scientists. Ulva mutabilis became an important model organism to study morphogenesis and mutualistic interactions of macroalgae and microorganisms. Here, we report that our collections of Ulva compressa Linnaeus (1753) from Germany are conspecific with the type strains of the model organism U. mutabilis Føyn (1958), which were originally collected at Olhão on the south coast of Portugal and have from that time on been maintained in culture as gametophytic and parthenogenetic lab strains. Different approaches were used to test conspecificity: (i) comparisons of vegetative and reproductive features of cultured material of U. mutabilis and German U. compressa demonstrated a shared morphological pattern; (ii) gametes of U. compressa and U. mutabilis successfully mated and developed into fertile sporophytic first-generation offspring; (iii) molecular phylogenetics and species delimitation analyses based on the Generalized Mixed Yule-Coalescent method showed that U. mutabilis isolates (sl-G[mt+]) and (wt-G[mt-]) and U. compressa belong to a unique Molecular Operational Taxonomic Unit. According to these findings, there is sufficient evidence that U. mutabilis and U. compressa should be regarded as conspecific.


Assuntos
Clorófitas , Alga Marinha , Ulva , Alemanha , Portugal
20.
Pharmacol Res Perspect ; 6(3): e00407, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29864245

RESUMO

The transcription factor Islet-1 marks a progenitor cell population of the second heart field during cardiogenesis. In the adult heart Islet-1 expression is limited to the sinoatrial node, the ventricular outflow tract, and parasympathetic ganglia. The regenerative effect in the injured mouse ventricle of thymosin beta-4 (TB4), a 43-aminoacid peptide, was associated with increased Islet-1 immunostaining, suggesting the induction of an Islet-1-positive progenitor state by TB4. Here we aimed to reassess this effect in a genetic model. Mice from the reporter mouse line Isl1-nLacZ were primed with TB4 and subsequently underwent myocardial infarction. Islet-1 expression was assessed 2, 7, and 14 days after infarction. We detected only a single Islet-1+ cell in 8 TB4 treated and infarcted hearts which located outside of the sinoatrial node, the outflow tract or cardiac ganglia (in ~2500 sections). Two cells were identified in 5 control infarcted hearts. TB4 did not induce LacZ positivity in ventricular explants cultures of Isl1-nLacZ mice nor did it affect the density of LacZ+ cells in explant cultures of nLacZ+ regions of the heart. In summary, we found no evidence that TB4 reactivates Islet-1 expression in adult mouse ventricle.


Assuntos
Ventrículos do Coração/efeitos dos fármacos , Proteínas com Homeodomínio LIM/genética , Proteínas com Homeodomínio LIM/metabolismo , Infarto do Miocárdio/genética , Timosina/administração & dosagem , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Animais , Células Cultivadas , Modelos Animais de Doenças , Regulação da Expressão Gênica , Ventrículos do Coração/citologia , Ventrículos do Coração/metabolismo , Camundongos , Camundongos Transgênicos , Nó Sinoatrial/citologia , Nó Sinoatrial/efeitos dos fármacos , Nó Sinoatrial/metabolismo , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo , Timosina/farmacologia
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