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1.
Trends Genet ; 40(5): 422-436, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38458877

RESUMO

Bdelloid rotifers constitute a class of microscopic animals living in freshwater habitats worldwide. Several strange features of bdelloids have drawn attention: their ability to tolerate desiccation and other stresses, a lack of reported males across the clade despite centuries of study, and unusually high numbers of horizontally acquired, non-metazoan genes. Genome sequencing is transforming our understanding of their lifestyle and its consequences, while in turn providing wider insights about recombination and genome organisation in animals. Many questions remain, not least how to reconcile apparent genomic signatures of sex with the continued absence of reported males, why bdelloids have so many horizontally acquired genes, and how their remarkable ability to survive stress interacts with recombination and other genomic processes.


Assuntos
Transferência Genética Horizontal , Recombinação Genética , Rotíferos , Estresse Fisiológico , Animais , Rotíferos/genética , Rotíferos/fisiologia , Transferência Genética Horizontal/genética , Estresse Fisiológico/genética , Reprodução Assexuada/genética , Genoma/genética , Genoma Helmíntico , Filogenia , Masculino
2.
Biol Cybern ; 118(3-4): 145-163, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38884785

RESUMO

Silent hypoxemia, or "happy hypoxia," is a puzzling phenomenon in which patients who have contracted COVID-19 exhibit very low oxygen saturation ( SaO 2 < 80%) but do not experience discomfort in breathing. The mechanism by which this blunted response to hypoxia occurs is unknown. We have previously shown that a computational model of the respiratory neural network (Diekman et al. in J Neurophysiol 118(4):2194-2215, 2017) can be used to test hypotheses focused on changes in chemosensory inputs to the central pattern generator (CPG). We hypothesize that altered chemosensory function at the level of the carotid bodies and/or the nucleus tractus solitarii are responsible for the blunted response to hypoxia. Here, we use our model to explore this hypothesis by altering the properties of the gain function representing oxygen sensing inputs to the CPG. We then vary other parameters in the model and show that oxygen carrying capacity is the most salient factor for producing silent hypoxemia. We call for clinicians to measure hematocrit as a clinical index of altered physiology in response to COVID-19 infection.


Assuntos
COVID-19 , Hipóxia , COVID-19/complicações , COVID-19/fisiopatologia , Humanos , Hipóxia/fisiopatologia , Respiração , Oxigênio/sangue , SARS-CoV-2
3.
Int J Mol Sci ; 24(11)2023 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-37298681

RESUMO

Intracellular Ca2+ signals are key for the regulation of cellular processes ranging from myocyte contraction, hormonal secretion, neural transmission, cellular metabolism, transcriptional regulation, and cell proliferation. Measurement of cellular Ca2+ is routinely performed using fluorescence microscopy with biological indicators. Analysis of deterministic signals is reasonably straightforward as relevant data can be discriminated based on the timing of cellular responses. However, analysis of stochastic, slower oscillatory events, as well as rapid subcellular Ca2+ responses, takes considerable time and effort which often includes visual analysis by trained investigators, especially when studying signals arising from cells embedded in complex tissues. The purpose of the current study was to determine if full-frame time-series and line-scan image analysis workflow of Fluo-4 generated Ca2+ fluorescence data from vascular myocytes could be automated without introducing errors. This evaluation was addressed by re-analyzing a published "gold standard" full-frame time-series dataset through visual analysis of Ca2+ signals from recordings made in pulmonary arterial myocytes of en face arterial preparations. We applied a combination of data driven and statistical approaches with comparisons to our published data to assess the fidelity of the various approaches. Regions of interest with Ca2+ oscillations were detected automatically post hoc using the LCPro plug-in for ImageJ. Oscillatory signals were separated based on event durations between 4 and 40 s. These data were filtered based on cutoffs obtained from multiple methods and compared to the published manually curated "gold standard" dataset. Subcellular focal and rapid Ca2+ "spark" events from line-scan recordings were examined using SparkLab 5.8, which is a custom automated detection and analysis program. After filtering, the number of true positives, false positives, and false negatives were calculated through comparisons to visually derived "gold standard" datasets. Positive predictive value, sensitivity, and false discovery rates were calculated. There were very few significant differences between the automated and manually curated results with respect to quality of the oscillatory and Ca2+ spark events, and there were no systematic biases in the data curation or filtering techniques. The lack of statistical difference in event quality between manual data curation and statistically derived critical cutoff techniques leads us to believe that automated analysis techniques can be reliably used to analyze spatial and temporal aspects to Ca2+ imaging data, which will improve experiment workflow.


Assuntos
Sinalização do Cálcio , Miócitos Cardíacos , Fluxo de Trabalho , Miócitos Cardíacos/metabolismo , Contração Muscular , Processamento de Imagem Assistida por Computador , Cálcio/metabolismo
4.
Annu Rev Genomics Hum Genet ; 19: 263-288, 2018 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-29799800

RESUMO

The genetic determinants of many diseases, including monogenic diseases and cancers, have been identified; nevertheless, targeted therapy remains elusive for most. High-throughput screening (HTS) of small molecules, including high-content analysis (HCA), has been an important technology for the discovery of molecular tools and new therapeutics. HTS can be based on modulation of a known disease target (called reverse chemical genetics) or modulation of a disease-associated mechanism or phenotype (forward chemical genetics). Prominent target-based successes include modulators of transthyretin, used to treat transthyretin amyloidoses, and the BCR-ABL kinase inhibitor Gleevec, used to treat chronic myelogenous leukemia. Phenotypic screening successes include modulators of cystic fibrosis transmembrane conductance regulator, splicing correctors for spinal muscular atrophy, and histone deacetylase inhibitors for cancer. Synthetic lethal screening, in which chemotherapeutics are screened for efficacy against specific genetic backgrounds, is a promising approach that merges phenotype and target. In this article, we introduce HTS technology and highlight its contributions to the discovery of drugs and probes for monogenic diseases and cancer.


Assuntos
Doenças Genéticas Inatas/tratamento farmacológico , Bibliotecas de Moléculas Pequenas/uso terapêutico , Proteínas de Fusão bcr-abl/antagonistas & inibidores , Ensaios de Triagem em Larga Escala , Humanos , Mesilato de Imatinib/farmacologia , Mesilato de Imatinib/uso terapêutico , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico
5.
PLoS Biol ; 16(4): e2004830, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29689044

RESUMO

Bdelloid rotifers are a class of microscopic invertebrates that have existed for millions of years apparently without sex or meiosis. They inhabit a variety of temporary and permanent freshwater habitats globally, and many species are remarkably tolerant of desiccation. Bdelloids offer an opportunity to better understand the evolution of sex and recombination, but previous work has emphasised desiccation as the cause of several unusual genomic features in this group. Here, we present high-quality whole-genome sequences of 3 bdelloid species: Rotaria macrura and R. magnacalcarata, which are both desiccation intolerant, and Adineta ricciae, which is desiccation tolerant. In combination with the published assembly of A. vaga, which is also desiccation tolerant, we apply a comparative genomics approach to evaluate the potential effects of desiccation tolerance and asexuality on genome evolution in bdelloids. We find that ancestral tetraploidy is conserved among all 4 bdelloid species, but homologous divergence in obligately aquatic Rotaria genomes is unexpectedly low. This finding is contrary to current models regarding the role of desiccation in shaping bdelloid genomes. In addition, we find that homologous regions in A. ricciae are largely collinear and do not form palindromic repeats as observed in the published A. vaga assembly. Consequently, several features interpreted as genomic evidence for long-term ameiotic evolution are not general to all bdelloid species, even within the same genus. Finally, we substantiate previous findings of high levels of horizontally transferred nonmetazoan genes in both desiccating and nondesiccating bdelloid species and show that this unusual feature is not shared by other animal phyla, even those with desiccation-tolerant representatives. These comparisons call into question the proposed role of desiccation in mediating horizontal genetic transfer.


Assuntos
Adaptação Fisiológica/genética , Especiação Genética , Genoma Helmíntico , Rotíferos/genética , Sintenia , Animais , Dessecação , Ecossistema , Água Doce , Transferência Genética Horizontal , Genômica/métodos , Filogenia , Rotíferos/classificação , Tetraploidia , Sequenciamento Completo do Genoma
6.
J Neuroinflammation ; 16(1): 269, 2019 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-31847862

RESUMO

BACKGROUND: Niemann-Pick disease type C (NPC) is a progressive neurodegenerative condition that results in early fatality. NPC is inherited in an autosomal recessive pattern from mutations in NPC1 or NPC2 genes. The etiology of NPC is poorly defined. In that regard, neuroinflammation occurs early in the disease and we have recently unveiled an atypical pattern of interferon signaling in pre-symptomatic Npc1-/- mice, with microglial activation, anti-viral response, activation of antigen-presenting cells, and activation and chemotaxis of T lymphocytes as the key affected pathologic pathways. Furthermore, IP-10/CXCL10, a potent IFN-γ-responsive cytokine, was identified as the potential mediator of these early inflammatory abnormalities. Here, we asked whether this aberrant signaling may be exacerbated by the loss of amyloid precursor protein (APP) function, a loss known to shorten lifespan and accelerate neurodegeneration in Npc1-/- mice. METHODS: We carried out genome-wide comparative transcriptome analyses of pre-symptomatic Npc1+/+/App+/+, Npc1-/-/App+/+, Npc1+/+/App-/-, and Npc1-/-/App-/- mouse cerebella to identify biological pathways in the NPC brain further affected by the loss of APP. Gene Set Enrichment Analysis and Ingenuity Pathway Analysis were utilized for molecular mapping and functional upstream pathway analyses of highly differentially expressed genes. We simultaneously measured the expression of 32 inflammatory cytokines and chemokines in the cerebella from these mice, including those identified in our genome-wide analyses. Finally, we used immunohistochemistry to measure T cell infiltration in the cerebellum. RESULTS: Expression of IFN-γ- and IFN-α-responsive genes in pre-symptomatic Npc1-/-/App-/- cerebella is upregulated compared with Npc1-/-/App+/+ mice, compounding the dysregulation of microglial activation, anti-viral response, activation of antigen-presenting cells, and T-lymphocyte activation and chemotaxis pathways present in the NPC brain. Multiplex protein analysis further showed elevated expression of IP-10/CXCL10, a potent downstream effector of IFN-γ, as well as RANTES/CCL5, eotaxin/CCL11 and IL-10, prior to symptomatic onset in Npc1-/-/App-/- cerebella, compared with Npc1-/-/App+/+mice. In the terminal disease stage, loss of APP caused pleiotropic differential expression of the vast majority of cytokines evaluated. Finally, we present evidence of T cell infiltration in Npc1-/-/App-/- cerebella. CONCLUSIONS: Loss of APP exacerbates the pathogenic neuroinflammation that occurs prior to symptomatic onset in the NPC brain. These findings shed new light on the function of APP as a cytoprotective modulator in the CNS, offering potential evidence-based therapies against NPC.


Assuntos
Precursor de Proteína beta-Amiloide/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Doença de Niemann-Pick Tipo C/metabolismo , Doença de Niemann-Pick Tipo C/patologia , Animais , Inflamação/metabolismo , Inflamação/patologia , Camundongos , Camundongos Knockout
7.
8.
Am J Physiol Regul Integr Comp Physiol ; 314(3): R433-R446, 2018 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-29167165

RESUMO

Long-term hypoxia (LTH) has a profound effect on pulmonary arterial vasoconstriction in the fetus and adult. Dysregulation in Ca2+ signaling is important during the development of LTH-induced pulmonary hypertension. In the present study, we tested the hypothesis that L-type Ca2+ channels (CaL), which are voltage dependent and found in smooth, skeletal, and cardiac muscle, are important in the adaptation of pulmonary arterial contractions in postnatal maturation and in response to LTH. Pulmonary arteries were isolated from fetal or adult sheep maintained at low or high altitude (3,801 m) for >100 days. The effects were measured using an L-type Ca2+ channel opener FPL 64176 (FPL) in the presence or absence of an inhibitor, Nifedipine (NIF) on arterial contractions, intracellular Ca2+ oscillations, and ryanodine receptor-driven Ca2+ sparks. FPL induced pulmonary arterial contractions in all groups were sensitive to NIF. However, when compared with 125 mM K+, FPL contractions were greater in fetuses than in adults. FPL reduced Ca2+ oscillations in myocytes of adult but not fetal arteries, independently of altitude. The FPL effects on Ca2+ oscillations were reversed by NIF in myocytes of hypoxic but not normoxic adults. FPL failed to enhance Ca2+ spark frequency and had little impact on spatiotemporal firing characteristics. These data suggest that CaL-dependent contractions are largely uncoupled from intracellular Ca2+ oscillations and the development of Ca2+ sparks. This raises questions regarding the coupling of pulmonary arterial contractility to membrane depolarization, attendant CaL facilitation, and the related associations with the activation of Ca2+ oscillations and Ca2+ sparks.


Assuntos
Doença da Altitude/metabolismo , Canais de Cálcio Tipo L/metabolismo , Sinalização do Cálcio , Cálcio/metabolismo , Artéria Pulmonar/metabolismo , Vasoconstrição , Doença da Altitude/fisiopatologia , Animais , Agonistas dos Canais de Cálcio/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio Tipo L/efeitos dos fármacos , Sinalização do Cálcio/efeitos dos fármacos , Modelos Animais de Doenças , Feminino , Coração Fetal/metabolismo , Coração Fetal/fisiopatologia , Idade Gestacional , Potenciais da Membrana , Miócitos Cardíacos/metabolismo , Gravidez , Artéria Pulmonar/efeitos dos fármacos , Artéria Pulmonar/embriologia , Artéria Pulmonar/fisiopatologia , Carneiro Doméstico , Fatores de Tempo , Vasoconstrição/efeitos dos fármacos
9.
Pediatr Res ; 83(2): 514-519, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29053705

RESUMO

BackgroundVagus nerve stimulation (VNS) is an Food and Drug Administration-approved method delivering electrical impulses for treatment of depression and epilepsy in adults. The vagus nerve innervates the majority of visceral organs and cervix, but potential impacts of VNS on the progress of pregnancy and the fetus are not well studied.MethodsWe tested the hypothesis that VNS in pregnant dams does not induce inflammatory changes in the cardio-respiratory control regions of the pups' brainstem, potentially impacting the morbidity and mortality of offspring. Pregnant dams were implanted with stimulators providing intermittent low or high frequency electrical stimulation of the sub-diaphragmatic esophageal segment of the vagus nerve for 6-7 days until delivery. After birth, we collected pup brainstems that included cardio-respiratory control regions and counted the cells labeled for pro-inflammatory cytokines (interleukin (IL)-1ß, IL-6, tumor necrosis factor-α) and high mobility group box 1.ResultsNeither pup viability nor number of cells labeled for pro-inflammatory cytokines in nucleus tractus solitarii or hypoglossal motor nucleus was impaired by VNS. We provide evidence suggesting that chronic VNS of pregnant mothers does not impede the progress or outcome of pregnancy.ConclusionVNS does not cause preterm birth, affect well-being of progeny, or impact central inflammatory processes that are critical for normal cardiovascular and respiratory function in newborns.


Assuntos
Tronco Encefálico/metabolismo , Inflamação , Estimulação do Nervo Vago , Nervo Vago/fisiologia , Animais , Tronco Encefálico/fisiologia , Sobrevivência Celular , Citocinas/metabolismo , Modelos Animais de Doenças , Estimulação Elétrica , Feminino , Parto , Gravidez , Prenhez , Ratos , Ratos Long-Evans , Respiração
10.
J Neurophysiol ; 118(4): 2194-2215, 2017 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-28724778

RESUMO

How sensory information influences the dynamics of rhythm generation varies across systems, and general principles for understanding this aspect of motor control are lacking. Determining the origin of respiratory rhythm generation is challenging because the mechanisms in a central circuit considered in isolation may be different from those in the intact organism. We analyze a closed-loop respiratory control model incorporating a central pattern generator (CPG), the Butera-Rinzel-Smith (BRS) model, together with lung mechanics, oxygen handling, and chemosensory components. We show that 1) embedding the BRS model neuron in a control loop creates a bistable system; 2) although closed-loop and open-loop (isolated) CPG systems both support eupnea-like bursting activity, they do so via distinct mechanisms; 3) chemosensory feedback in the closed loop improves robustness to variable metabolic demand; 4) the BRS model conductances provide an autoresuscitation mechanism for recovery from transient interruption of chemosensory feedback; and 5) the in vitro brain stem CPG slice responds to hypoxia with transient bursting that is qualitatively similar to in silico autoresuscitation. Bistability of bursting and tonic spiking in the closed-loop system corresponds to coexistence of eupnea-like breathing, with normal minute ventilation and blood oxygen level and a tachypnea-like state, with pathologically reduced minute ventilation and critically low blood oxygen. Disruption of the normal breathing rhythm, through either imposition of hypoxia or interruption of chemosensory feedback, can push the system from the eupneic state into the tachypneic state. We use geometric singular perturbation theory to analyze the system dynamics at the boundary separating eupnea-like and tachypnea-like outcomes.NEW & NOTEWORTHY A common challenge facing rhythmic biological processes is the adaptive regulation of central pattern generator (CPG) activity in response to sensory feedback. We apply dynamical systems tools to understand several properties of a closed-loop respiratory control model, including the coexistence of normal and pathological breathing, robustness to changes in metabolic demand, spontaneous autoresuscitation in response to hypoxia, and the distinct mechanisms that underlie rhythmogenesis in the intact control circuit vs. the isolated, open-loop CPG.


Assuntos
Geradores de Padrão Central/fisiologia , Retroalimentação Fisiológica , Modelos Neurológicos , Respiração , Centro Respiratório/fisiologia , Taquipneia/fisiopatologia , Células Quimiorreceptoras/fisiologia , Humanos , Oxigênio/sangue
11.
J Manipulative Physiol Ther ; 40(2): 77-88, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27964876

RESUMO

OBJECTIVE: The purpose of this study was to develop a method for applying calibrated manual massage pressures by using commonly available, inexpensive sphygmomanometer parts and validate the use of this approach as a quantitative method of applying massage therapy to rodents. METHODS: Massage pressures were monitored by using a modified neonatal blood pressure (BP) cuff attached to an aneroid gauge. Lightly anesthetized rats were stroked on the ventral abdomen for 5 minutes at pressures of 20 mm Hg and 40 mm Hg. Blood pressure was monitored noninvasively for 20 minutes following massage therapy at 5-minute intervals. Interexaminer reliability was assessed by applying 20 mm Hg and 40 mm Hg pressures to a digital scale in the presence or absence of the pressure gauge. RESULTS: With the use of this method, we observed good interexaminer reliability, with intraclass coefficients of 0.989 versus 0.624 in blinded controls. In Long-Evans rats, systolic BP dropped by an average of 9.86% ± 0.27% following application of 40 mm Hg massage pressure. Similar effects were seen following 20 mm Hg pressure (6.52% ± 1.7%), although latency to effect was greater than at 40 mm Hg. Sprague-Dawley rats behaved similarly to Long-Evans rats. Low-frequency/high-frequency ratio, a widely-used index of autonomic tone in cardiovascular regulation, showed a significant increase within 5 minutes after 40 mm Hg massage pressure was applied. CONCLUSIONS: The calibrated massage method was shown to be a reproducible method for applying massage pressures in rodents and lowering BP.


Assuntos
Pressão Sanguínea/fisiologia , Frequência Cardíaca/fisiologia , Massagem/métodos , Abdome/fisiologia , Animais , Sistema Nervoso Autônomo/fisiologia , Masculino , Modelos Animais , Ratos , Ratos Long-Evans , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Esfigmomanômetros , Sístole
12.
Biochem J ; 465(1): 149-61, 2015 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-25287889

RESUMO

Zeta-chain associated protein of 70 kDa (ZAP-70) and spleen tyrosine kinase (Syk) are non-receptor tyrosine kinases that are essential for T-cell and B-cell antigen receptor signalling respectively. They are recruited, via their tandem-SH2 (Src-homology domain 2) domains, to doubly phosphorylated immunoreceptor tyrosine-based activation motifs (ITAMs) on invariant chains of immune antigen receptors. Because of their critical roles in immune signalling, ZAP-70 and Syk are targets for the development of drugs for autoimmune diseases. We show that three thiol-reactive small molecules can prevent the tandem-SH2 domains of ZAP-70 and Syk from binding to phosphorylated ITAMs. We identify a specific cysteine residue in the phosphotyrosine-binding pocket of each protein (Cys39 in ZAP-70, Cys206 in Syk) that is necessary for inhibition by two of these compounds. We also find that ITAM binding to ZAP-70 and Syk is sensitive to the presence of H2O2 and these two cysteine residues are also necessary for inhibition by H2O2. Our findings suggest a mechanism by which the reactive oxygen species generated during responses to antigen could attenuate signalling through these kinases and may also inform the development of ZAP-70 and Syk inhibitors that bind covalently to their SH2 domains.


Assuntos
Cisteína/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/química , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Fosfopeptídeos/metabolismo , Proteínas Tirosina Quinases/química , Proteínas Tirosina Quinases/metabolismo , Proteína-Tirosina Quinase ZAP-70/química , Proteína-Tirosina Quinase ZAP-70/metabolismo , Domínios de Homologia de src , Motivos de Aminoácidos , Sítios de Ligação , Humanos , Peróxido de Hidrogênio/farmacologia , Modelos Moleculares , Oxirredução/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Fosfotirosina/metabolismo , Ligação Proteica/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Compostos de Sulfidrila/metabolismo , Quinase Syk , Proteína-Tirosina Quinase ZAP-70/antagonistas & inibidores
13.
J Physiol ; 598(21): 4747-4748, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32897585
14.
Front Nutr ; 11: 1394632, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39262430

RESUMO

There has been a sea of change in our understanding of the contribution of food to both our well-being and disease states. When one addresses "food as medicine," the concept of oxidative stress needs to be included. This review interconnects the basic science findings of oxidative stress and redox balance with the medicinal use of food, emphasizing optimization of the redox balance. To better illustrate the impacts of oxidative stress, the concept of the "triple oxidant sink" is introduced as a theoretical gauge of redox balance. Utilizing the concept, the true importance of dietary and lifestyle factors can be emphasized, including the limitations of supplements or a handful of "superfoods," if the remainder of the factors are pro-oxidant. The effects of a whole plant food diet compared with those of dietary supplements, processed foods, animal based nutrients, or additional lifestyle factors can be visually demonstrated with this concept. This paper provides an overview of the process, acknowledging that food is not the only mechanism for balancing the redox status, but one that can be strategically used to dramatically improve the oxidative state, and thus should be used as medicine.

15.
Nat Commun ; 15(1): 5787, 2024 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-39025839

RESUMO

Coevolutionary antagonism generates relentless selection that can favour genetic exchange, including transfer of antibiotic synthesis and resistance genes among bacteria, and sexual recombination of disease resistance alleles in eukaryotes. We report an unusual link between biological conflict and DNA transfer in bdelloid rotifers, microscopic animals whose genomes show elevated levels of horizontal gene transfer from non-metazoan taxa. When rotifers were challenged with a fungal pathogen, horizontally acquired genes were over twice as likely to be upregulated as other genes - a stronger enrichment than observed for abiotic stressors. Among hundreds of upregulated genes, the most markedly overrepresented were clusters resembling bacterial polyketide and nonribosomal peptide synthetases that produce antibiotics. Upregulation of these clusters in a pathogen-resistant rotifer species was nearly ten times stronger than in a susceptible species. By acquiring, domesticating, and expressing non-metazoan biosynthetic pathways, bdelloids may have evolved to resist natural enemies using antimicrobial mechanisms absent from other animals.


Assuntos
Transferência Genética Horizontal , Rotíferos , Animais , Rotíferos/genética , Rotíferos/metabolismo , Vias Biossintéticas/genética , Peptídeo Sintases/genética , Peptídeo Sintases/metabolismo , Policetídeos/metabolismo , Filogenia , Família Multigênica
16.
Genes (Basel) ; 15(1)2024 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-38254990

RESUMO

Niemann-Pick disease type C (NPC) is a fatal neurodegenerative condition caused by genetic mutations of the NPC1 or NPC2 genes that encode the NPC1 and NPC2 proteins, respectively, which are believed to be responsible for cholesterol efflux from late-endosomes/lysosomes. The pathogenic mechanisms that lead to neurodegeneration in NPC are not well understood. There are, however, well-defined spatiotemporal patterns of neurodegeneration that may provide insight into the pathogenic process. For example, the cerebellum is severely affected from early disease stages, compared with cerebral regions, which remain relatively spared until later stages. Using a genome-wide transcriptome analysis, we have recently identified an aberrant pattern of interferon activation in the cerebella of pre-symptomatic Npc1-/- mice. Here, we carried out a comparative transcriptomic analysis of cerebral cortices and cerebella of pre-symptomatic Npc1-/- mice and age-matched controls to identify differences that may help explain the pathological progression within the NPC brain. We report lower cerebral expression of genes within interferon signaling pathways, and significant differences in the regulation of oxidative stress, compared with the cerebellum. Our findings suggest that a delayed onset of interferon signaling, possibly linked to lower oxidative stress, may account for the slower onset of cerebral cortical pathology in the disease.


Assuntos
Doença de Niemann-Pick Tipo C , Animais , Camundongos , Doença de Niemann-Pick Tipo C/genética , Cerebelo , Córtex Cerebral , Estresse Oxidativo , Interferons/genética
17.
Biomed Pharmacother ; 171: 116081, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38219385

RESUMO

L-cysteine ethylester (L-CYSee) is a membrane-permeable analogue of L-cysteine with a variety of pharmacological effects. The purpose of this study was to determine the effects of L-CYSee on morphine-induced changes in ventilation, arterial-blood gas (ABG) chemistry, Alveolar-arterial (A-a) gradient (i.e., a measure of the index of alveolar gas-exchange), antinociception and sedation in male Sprague Dawley rats. An injection of morphine (10 mg/kg, IV) produced adverse effects on breathing, including sustained decreases in minute ventilation. L-CYSee (500 µmol/kg, IV) given 15 min later immediately reversed the actions of morphine. Another injection of L-CYSee (500 µmol/kg, IV) after 15 min elicited more pronounced excitatory ventilatory responses. L-CYSee (250 or 500 µmol/kg, IV) elicited a rapid and prolonged reversal of the actions of morphine (10 mg/kg, IV) on ABG chemistry (pH, pCO2, pO2, sO2) and A-a gradient. L-serine ethylester (an oxygen atom replaces the sulfur; 500 µmol/kg, IV), was ineffective in all studies. L-CYSee (500 µmol/kg, IV) did not alter morphine (10 mg/kg, IV)-induced sedation, but slightly reduced the overall duration of morphine (5 or 10 mg/kg, IV)-induced analgesia. In summary, L-CYSee rapidly overcame the effects of morphine on breathing and alveolar gas-exchange, while not affecting morphine sedation or early-stage analgesia. The mechanisms by which L-CYSee modulates morphine depression of breathing are unknown, but appear to require thiol-dependent processes.


Assuntos
Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Morfina , Ratos , Masculino , Animais , Morfina/farmacologia , Cisteína/farmacologia , Ratos Sprague-Dawley , Respiração , Gasometria , Dor
18.
Proc Biol Sci ; 280(1765): 20131255, 2013 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-23825214

RESUMO

Sexual reproduction is costly, but it is nearly ubiquitous among plants and animals, whereas obligately asexual taxa are rare and almost always short-lived. The Red Queen hypothesis proposes that sex overcomes its costs by enabling organisms to keep pace with coevolving parasites and pathogens. If so, the few cases of stable long-term asexuality ought to be found in groups whose coevolutionary interactions with parasites are unusually weak. In theory, antagonistic coevolution will be attenuated if hosts disperse among patches within a metapopulation separately from parasites and more rapidly. We examined whether these conditions are met in natural communities of bdelloid rotifers, one of the longest-lived asexual lineages. At any life stage, these microscopic invertebrates can tolerate the complete desiccation of their ephemeral freshwater habitats, surviving as dormant propagules that are readily carried by the wind. In our field experiments, desiccation and wind transport enabled bdelloids to disperse independently of multiple fungal parasites, in both time and space. Surveys of bdelloid communities in unmanipulated moss patches confirmed that fungal parasitism was negatively correlated with extended drought and increasing height (exposure to wind). Bdelloid ecology therefore matches a key condition of models in which asexuals persist through spatio-temporal decoupling from coevolving enemies.


Assuntos
Ecossistema , Fungos/fisiologia , Rotíferos/microbiologia , Análise Espaço-Temporal , Animais , Evolução Biológica , Dessecação , Fungos/isolamento & purificação , Reprodução/genética , Reprodução Assexuada/genética , Rotíferos/genética , Rotíferos/fisiologia , Simbiose , Vento
19.
Drug Discov Today Technol ; 10(4): e501-8, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24451641

RESUMO

There is strong interest in developing small molecules that modulate protein-protein interactions (PPI), since such compounds could serve as drug leads or as probes of protein function. Fragment-based ligand discovery has been a particularly useful approach for modulating PPI. Fragments are typically <250 Da compounds that bind to proteins with weak affinity but high ligand efficiency. Here, we review a method for fragment- based ligand discovery using covalent disulfide trapping (Tethering). Tethering uses a native or engineered cysteine residue to select thiol-containing fragments that bind to the protein near the tethering cysteine. Taking advantage of the site-directed nature of Tethering, one can investigate the 'druggability' of particular binding sites on a protein surface; furthermore, Tethering has been used to find new binding sites and to stabilize allosteric conformations. We review the principles of Tethering and discuss two examples where disulfide trapping has expanded our understanding of PPI. For the cytokine interleukin-2 (IL2), Tethering identified a binding site adjacent to the IL2/IL2- receptor and a new site allosterically coupled to this PPI. For the kinase PDK1, Tethering identified ligands that activated or inhibited enzymatic activity by bind-ing to a single allosteric site. These examples provide a context for successful fragment-discovery projects, in which complementary technologies work together to identify starting points for chemical biology and drug discovery.


Assuntos
Descoberta de Drogas , Preparações Farmacêuticas/metabolismo , Interleucina-2/química , Interleucina-2/metabolismo , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Mapeamento de Interação de Proteínas , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/metabolismo , Piruvato Desidrogenase Quinase de Transferência de Acetil
20.
Curr Biol ; 33(9): R371-R374, 2023 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-37160098

RESUMO

Sighs are a response to hypoxia, altered lung volume, and emotional state. A recent study employing in vivo physiology, optogenetics, chemoablation, and genetic silencing shows the importance of gastrin releasing peptide-expressing neurons in mediating sighs.


Assuntos
Emoções , Respiração , Humanos , Peptídeo Liberador de Gastrina , Inativação Gênica , Hipóxia
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