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1.
Adv Physiol Educ ; 45(1): 31-33, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33439784

RESUMO

The COVID-19 pandemic forced academics to switch to online teaching whether they were prepared or not. The speed and enthusiasm with which educators embraced online teaching suggest that challenges change the perspective for the better. The teaching challenges with the current coronavirus situation mimic the poliovirus attack Dr. Arthur C. Guyton encountered. Dr. Guyton was forced to switch his career from becoming a cardiovascular surgeon to a physiology educator and a researcher. His immense contributions to the field of physiology is an example of how challenges can bring benefits. Flipped teaching has been gaining attention among educators because of its ability to engage students in learning. The COVID-19 pandemic pushed educators to adopt this instructional design based on its conduciveness to technology, as well as its blend of both asynchronous and synchronous components of online teaching. Just like Dr. Guyton's enormous impact on medical education and research in spite of the challenges he faced, we must be creative during this pandemic through innovative teaching methods, which will serve as a gift for the future of physiology education.


Assuntos
Adaptação Fisiológica/fisiologia , Educação a Distância/métodos , Educação Médica/métodos , Fisiologia/educação , Educação a Distância/tendências , Educação Médica/tendências , Humanos
2.
Ecotoxicol Environ Saf ; 211: 111914, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33454593

RESUMO

Bioremediation of Cd contaminated environments can be assisted by plant-growth-promoting bacteria (PGPB) enabling plant growth in these sites. Here a gram-negative Burkholderia contaminans ZCC was isolated from mining soil at a copper-gold mine. When exposed to Cd(II), ZCC displayed high Cd resistance and the minimal inhibitory concentration was 7 mM in LB medium. Complete genome analysis uncovered B. contaminans ZCC contained 3 chromosomes and 2 plasmids. One of these plasmids was shown to contain a multitude of heavy metal resistance determinants including genes encoding a putative Cd-translocating PIB-type ATPase and an RND-type related to the Czc-system. These additional heavy metal resistance determinants are likely responsible for the increased resistance to Cd(II) and other heavy metals in comparison to other strains of B. contaminans. B. contaminans ZCC also displayed PGPB traits such as 1-aminocyclopropane-1-carboxylate deaminase activity, siderophore production, organic and inorganic phosphate solubilization and indole acetic acid production. Moreover, the properties and Cd(II) binding characteristics of extracellular polymeric substances was investigated. ZCC was able to induce extracellular polymeric substances production in response to Cd and was shown to be chemically coordinated to Cd(II). It could promote the growth of soybean in the presence of elevated concentrations of Cd(II). This work will help to better understand processes important in bioremediation of Cd-contaminated environment.


Assuntos
Adaptação Fisiológica/fisiologia , Burkholderia/fisiologia , Cádmio/toxicidade , Poluentes do Solo/toxicidade , Biodegradação Ambiental , Cádmio/metabolismo , Ácidos Indolacéticos , Metais Pesados/análise , Mineração , Desenvolvimento Vegetal , Solo/química , Microbiologia do Solo , Poluentes do Solo/análise , Soja/metabolismo
3.
Chemosphere ; 263: 127934, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32828055

RESUMO

A high ammonia concentration and chemical oxygen demand (COD) in piggery wastewater force it to be diluted before conventional microalgal treatment to reduce ammonia toxicity. Incomplete treatment of ammonia and COD in piggery wastewater may cause eutrophication, resulting in algal blooms. This study tried to treat raw piggery wastewater without dilution, using three strains of microalgae (Chlorella sorokiniana, Coelastrella sp. and Acutodesmus nygaardii) that outcompeted other algae under heterotrophic, mixotrophic, and autotrophic conditions, respectively, through adaptive evolution at high ammonia concentration. The three stepwise processes were designed to remove (1) small particles, COD, and phosphorus in the 1st heterotrophic C. sorokiniana cultivation, (2) ammonia and COD in the 2nd mixotrophic Coelastrella sp. cultivation, and (3) the remaining ammonia in the 3rd photoautotrophic A. nygaardii cultivation. To enhance ammonia uptake rate, each algal species were inoculated after 2-day nitrogen starvation. When the N-starved three species were inoculated at each step sequentially at 7 g/L for 2 days, the final phosphorus, COD, and ammonia removal efficiencies were 100% (16.4-0 mg/L), 92% (6820-545 mg/L), 90% (850-81 mg/L) and turbidity (99%) after total 6 days.


Assuntos
Adaptação Fisiológica/fisiologia , Amônia/metabolismo , Biodegradação Ambiental , Microalgas/fisiologia , Eliminação de Resíduos Líquidos/métodos , Animais , Processos Autotróficos , Análise da Demanda Biológica de Oxigênio , Biomassa , Chlorella , Processos Heterotróficos , Nitrogênio , Fósforo , Suínos , Águas Residuárias
4.
Ecotoxicol Environ Saf ; 209: 111761, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33333341

RESUMO

Cobalt (Co) and copper (Cu) co-exist commonly in the contaminated soils and at excessive levels, they are toxic to plants. However, their joint effect and possible interaction have not been fully addressed. In this work, a hydroponic experiment was performed to investigate the combined effects of Co and Cu on two barley genotypes at transcriptional level by RNA-seq analysis. The results identified 358 genes inclusively expressed in both genotypes under single and combined treatments of Co and Cu, with most of them being related to metal transport, stress response and transcription factor. The combined treatment induced more differently expressed genes (DEGs) than the single treatment, with Yan66, a metal tolerant genotype having more DEGs than Ea52, a sensitive genotype. The pathways associated with anthocyanin biosynthesis, MAPK signaling, glutathione biosynthesis, phenylalanine metabolism, photosynthesis, arginin biosynthesis, fatty acid elongation, and plant hormone signal transduction biosynthesis were induced and inhibited in Yan66 and Ea52, respectively. Furthermore, flavonoid biosynthesis was much more largely enhanced and accordingly more free flavonoid components (naringin, narirutin and neohesperidin) were accumulated in Yan66 than in Ea52. It may be suggested that high tolerance to both Co and Cu in Yan66 is attributed to its high gene regulatory ability.


Assuntos
Cobalto/toxicidade , Cobre/metabolismo , Hordeum/fisiologia , Adaptação Fisiológica/fisiologia , Cobalto/metabolismo , Cobre/toxicidade , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genótipo , Hordeum/efeitos dos fármacos , Hordeum/genética , Hidroponia , Fotossíntese/efeitos dos fármacos , Reguladores de Crescimento de Planta/metabolismo , Estresse Fisiológico , Fatores de Transcrição/genética , Transcriptoma
5.
Ecotoxicol Environ Saf ; 209: 111793, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33360287

RESUMO

Arsenic (As) toxicity can be a hazardous threat to sustainable agriculture and human health. Piriformospora indica (P. indica), as a beneficial endophytic fungus, is involved in the plant tolerance to stressful conditions. Here, the biochemical and molecular responses of rice plants to As (50 µM) phytotoxicity and P. indica inoculation as well as the role of P. indica in improving rice adaptation to As stress were evaluated. The results showed that As stress reduced chlorophylls content, chlorophyll fluorescence yield (Fv/Fm), electron transport rate (ETR) and growth. However, P. indica restored chlorophyll content and growth. P. indica decreased the contents of methylglyoxal and malondialdehyde by improving the activity of enzymes involved in the glyoxalase pathway and modulating the redox state of the ascorbic acid-glutathione cycle, and consequently, increased the plant tolerance to As toxicity. P. indica, by downregulating Lsi2 expression (involved in As translocation to the shoot) and upregulating PCS1 and PCS2 expression (involved in As sequestration in vacuoles), immobilized As in the roots and reduced damage to photosynthetic organs. P. indica increased iron (Fe) accumulation in the shoot under As toxicity by upregulating the expression of IRO2, YSL2 and FRDL1 genes. The results of the present study augmented our knowledge in using P. indica symbiosis in improving the tolerance of rice plants against As toxicity for sustainable agriculture.


Assuntos
Adaptação Fisiológica/fisiologia , Arsênico/toxicidade , Basidiomycota/fisiologia , Oryza/fisiologia , Poluentes do Solo/toxicidade , Arsênico/metabolismo , Basidiomycota/metabolismo , Clorofila/metabolismo , Humanos , Ferro/metabolismo , Malondialdeído/metabolismo , Oryza/metabolismo , Oryza/microbiologia , Fotossíntese , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Poluentes do Solo/metabolismo , Simbiose
6.
Neural Netw ; 134: 173-204, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33316723

RESUMO

We consider a cerebellar ring network for the optokinetic response (OKR), and investigate the effect of diverse recoding of granule (GR) cells on OKR by varying the connection probability pc from Golgi to GR cells. For an optimal value of pc∗(=0.06), individual GR cells exhibit diverse spiking patterns which are in-phase, anti-phase, or complex out-of-phase with respect to their population-averaged firing activity. Then, these diversely-recoded signals via parallel fibers (PFs) from GR cells are effectively depressed by the error-teaching signals via climbing fibers from the inferior olive which are also in-phase ones. Synaptic weights at in-phase PF-Purkinje cell (PC) synapses of active GR cells are strongly depressed via strong long-term depression (LTD), while those at anti-phase and complex out-of-phase PF-PC synapses are weakly depressed through weak LTD. This kind of "effective" depression (i.e., strong/weak LTD) at the PF-PC synapses causes a big modulation in firings of PCs, which then exert effective inhibitory coordination on the vestibular nucleus (VN) neuron (which evokes OKR). For the firing of the VN neuron, the learning gain degree Lg, corresponding to the modulation gain ratio, increases with increasing the learning cycle, and it saturates at about the 300th cycle. By varying pc from pc∗, we find that a plot of saturated learning gain degree Lg∗ versus pc forms a bell-shaped curve with a peak at pc∗ (where the diversity degree in spiking patterns of GR cells is also maximum). Consequently, the more diverse in recoding of GR cells, the more effective in motor learning for the OKR adaptation.


Assuntos
Cerebelo/citologia , Cerebelo/fisiologia , Rede Nervosa/fisiologia , Plasticidade Neuronal/fisiologia , Nistagmo Optocinético/fisiologia , Adaptação Fisiológica/fisiologia , Animais , Depressão Sináptica de Longo Prazo/fisiologia , Células de Purkinje/fisiologia , Sinapses/fisiologia
7.
PLoS One ; 15(12): e0243425, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33362279

RESUMO

Identifying priority conservation areas plays a significant role in conserving biodiversity under climate change, but uncertainties create challenges for conservation planning. To reduce uncertainties in the conservation planning framework, we developed an adaptation index to assess the effect of topographic complexity on species adaptation to climate change, which was incorporated into the conservation framework as conservation costs. Meanwhile, the species distributions were predicted by the Maxent model, and the priority conservation areas were optimized during different periods in Sichuan province by the Marxan model. Our results showed that the effect of topographic complexity was critical for species adaptation, but the adaptation index decreased with the temperature increase. Based on the conservation targets and costs, the distributions of priority conservation areas were mainly concentrated in mountainous areas around the Sichuan Basin where may be robust to the adaptation to climate change. In the future, the distributions of priority conservation areas had no evident changes, accounting for about 26% and 28% of the study areas. Moreover, most species habitats could be conserved in terms of conservation targets in these priority conservation areas. Therefore, our approach could achieve biodiversity conservation goals and be highly practical. More importantly, quantifying the effect of topography also is critical for options for planning conservation areas in response to climate change.


Assuntos
Adaptação Fisiológica/fisiologia , Biodiversidade , Mudança Climática , Conservação dos Recursos Naturais , China , Ecossistema , Humanos
8.
PLoS Biol ; 18(12): e3000987, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33332354

RESUMO

The antimicrobial resistance crisis has persisted despite broad attempts at intervention. It has been proposed that an important driver of resistance is selection imposed on bacterial populations that are not the intended target of antimicrobial therapy. But to date, there has been limited quantitative measure of the mean and variance of resistance following antibiotic exposure. Here we focus on the important nosocomial pathogen Enterococcus faecium in a hospital system where resistance to daptomycin is evolving despite standard interventions. We hypothesized that the intravenous use of daptomycin generates off-target selection for resistance in transmissible gastrointestinal (carriage) populations of E. faecium. We performed a cohort study in which the daptomycin resistance of E. faecium isolated from rectal swabs from daptomycin-exposed patients was compared to a control group of patients exposed to linezolid, a drug with similar indications. In the daptomycin-exposed group, daptomycin resistance of E. faecium from the off-target population was on average 50% higher than resistance in the control group (n = 428 clones from 22 patients). There was also greater phenotypic diversity in daptomycin resistance within daptomycin-exposed patients. In patients where multiple samples over time were available, a wide variability in temporal dynamics were observed, from long-term maintenance of resistance to rapid return to sensitivity after daptomycin treatment stopped. Sequencing of isolates from a subset of patients supports the argument that selection occurs within patients. Our results demonstrate that off-target gastrointestinal populations rapidly respond to intravenous antibiotic exposure. Focusing on the off-target evolutionary dynamics may offer novel avenues to slow the spread of antibiotic resistance.


Assuntos
Daptomicina/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Adaptação Fisiológica/efeitos dos fármacos , Adaptação Fisiológica/fisiologia , Adulto , Antibacterianos/uso terapêutico , Estudos de Coortes , Enterococcus faecium/efeitos dos fármacos , Enterococcus faecium/metabolismo , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Filogenia , Vancomicina/farmacologia , Enterococos Resistentes à Vancomicina/metabolismo
9.
BMC Med ; 18(1): 395, 2020 12 24.
Artigo em Inglês | MEDLINE | ID: mdl-33357243

RESUMO

BACKGROUND: Fetal growth restriction (FGR) due to placental insufficiency is a major risk factor for stillbirth. While small-for-gestational-age (SGA; weight < 10th centile) is a commonly used proxy for FGR, detection of FGR among appropriate-for-gestational-age (AGA; weight ≥ 10th centile) fetuses remains an unmet need in clinical care. We aimed to determine whether reduced antenatal growth velocity from the time of routine mid-trimester ultrasound is associated with antenatal, intrapartum and postnatal indicators of placental insufficiency among term AGA infants. METHODS: Three hundred and five women had biometry measurements recorded from their routine mid-trimester (20-week) ultrasound, at 28 and 36 weeks' gestation, and delivered an AGA infant. Mid-trimester, 28- and 36-week estimated fetal weight (EFW) and abdominal circumference (AC) centiles were calculated. The EFW and AC growth velocities between 20 and 28 weeks, and 20-36 weeks, were examined as predictors of four clinical indicators of placental insufficiency: (i) low 36-week cerebroplacental ratio (CPR; CPR < 5th centile reflects cerebral redistribution-a fetal adaptation to hypoxia), (ii) neonatal acidosis (umbilical artery pH < 7.15) after the hypoxic challenge of labour, (iii) low neonatal body fat percentage (BF%) reflecting reduced nutritional reserve and (iv) placental weight < 10th centile. RESULTS: Declining 20-36-week fetal growth velocity was associated with all indicators of placental insufficiency. Each one centile reduction in EFW between 20 and 36 weeks increased the odds of cerebral redistribution by 2.5% (odds ratio (OR) = 1.025, P = 0.001), the odds of neonatal acidosis by 2.7% (OR = 1.027, P = 0.002) and the odds of a < 10th centile placenta by 3.0% (OR = 1.030, P < 0.0001). Each one centile reduction in AC between 20 and 36 weeks increased the odds of neonatal acidosis by 3.1% (OR = 1.031, P = 0.0005), the odds of low neonatal BF% by 2.8% (OR = 1.028, P = 0.04) and the odds of placenta < 10th centile by 2.1% (OR = 1.021, P = 0.0004). Falls in EFW or AC of > 30 centiles between 20 and 36 weeks were associated with two-threefold increased relative risks of these indicators of placental insufficiency, while low 20-28-week growth velocities were not. CONCLUSIONS: Reduced growth velocity between 20 and 36 weeks among AGA fetuses is associated with antenatal, intrapartum and postnatal indicators of placental insufficiency. These fetuses potentially represent an important, under-recognised cohort at increased risk of stillbirth. Encouragingly, this novel fetal assessment would require only one additional ultrasound to current routine care, and adds to the potential benefits of routine 36-week ultrasound.


Assuntos
Adaptação Fisiológica/fisiologia , Desenvolvimento Fetal/fisiologia , Retardo do Crescimento Fetal/etiologia , Peso Corporal Ideal , Insuficiência Placentária , Segundo Trimestre da Gravidez/fisiologia , Adulto , Peso ao Nascer , Estudos de Coortes , Feminino , Retardo do Crescimento Fetal/diagnóstico , Retardo do Crescimento Fetal/epidemiologia , Peso Fetal/fisiologia , Idade Gestacional , Humanos , Recém-Nascido , Masculino , Insuficiência Placentária/diagnóstico , Insuficiência Placentária/epidemiologia , Insuficiência Placentária/fisiopatologia , Gravidez , Fatores de Risco , Ultrassonografia Pré-Natal , Artérias Umbilicais/diagnóstico por imagem , Adulto Jovem
10.
Anim Sci J ; 91(1): e13481, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33161615

RESUMO

This study investigated the effect of adaptation to grazing in early spring on herbage intake, ruminal fermentation parameters, blood metabolite concentrations, and body weight change in dairy cows. The experiment was conducted on eight rumen-cannulated non-lactating cows in the early spring period. Four cows were adapted to grazing by stocking for 4 hr for 1 week (ADP group). The other cows were kept in a barn during the period (CON group). Then, both groups of cows were stocked together throughout a day on a 1 ha pasture for 3 weeks (experimental period). In the first week of the experimental period, compared to the CON group, the ADP group had a higher herbage intake, ruminal NH3 -N and total VFA concentration, and blood urea concentration, but the NEFA concentration was lower in the ADP group (p < .01). During the subsequent weeks, there were little differences in ruminal fermentation parameters and blood metabolites. Cows in the ADP group maintained their body weight, but cows in the CON group lost 60 kg of body weight in the first week of the experimental period.


Assuntos
Adaptação Fisiológica/fisiologia , Fenômenos Fisiológicos da Nutrição Animal/fisiologia , Peso Corporal , Bovinos/metabolismo , Bovinos/fisiologia , Ingestão de Alimentos/fisiologia , Fermentação , Herbivoria/fisiologia , Rúmen/metabolismo , Estações do Ano , Amônia/metabolismo , Animais , Nitrogênio da Ureia Sanguínea , Feminino , Nitrogênio/metabolismo , Fatores de Tempo
13.
PLoS One ; 15(9): e0239032, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32925937

RESUMO

Knowing where our limbs are in space is essential for moving and for adapting movements to various changes in our environments and bodies. The ability to adapt movements declines with age, and age-related cognitive decline can explain a decreased ability to adopt and deploy explicit, cognitive strategies in motor learning. Age-related sensory decline could also lead to a reduced fidelity of sensory position signals and error signals, each of which can affect implicit motor adaptation. Here we investigate two estimates of limb position; one based on proprioception, the other on predicted sensory consequences of movements. Each is considered a measure of an implicit adaptation process and may be affected by both age and cognitive strategies. Both older (n = 38) and younger (n = 42) adults adapted to a 30° visuomotor rotation in a centre-out reaching task. We make an explicit, cognitive strategy available to half of participants in each age group with a detailed instruction. After training, we first quantify the explicit learning elicited by instruction. Instructed older adults initially use the provided strategy slightly less than younger adults but show a similar ability to evoke it after training. This indicates that cognitive explanations for age-related decline in motor learning are limited. In contrast, training induced much larger shifts of state estimates of hand location in older adults compared to younger adults. This is not modulated by strategy instructions, and appears driven by recalibrated proprioception, which is almost twice as large in older adults, while predictions might not be updated in older adults. This means that in healthy aging, some implicit processes may be compensating for other changes to maintain motor capabilities, while others also show age-related decline (data: https://osf.io/qzhmy).


Assuntos
Fatores Etários , Atividade Motora/fisiologia , Desempenho Psicomotor/fisiologia , Adaptação Fisiológica/fisiologia , Adaptação Psicológica/fisiologia , Idoso , Feminino , Mãos/fisiologia , Humanos , Aprendizagem/fisiologia , Masculino , Movimento , Propriocepção , Rotação , Adulto Jovem
14.
Proc Natl Acad Sci U S A ; 117(38): 23932-23941, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32900951

RESUMO

DICER is a key enzyme in microRNA (miRNA) biogenesis. Here we show that aerobic exercise training up-regulates DICER in adipose tissue of mice and humans. This can be mimicked by infusion of serum from exercised mice into sedentary mice and depends on AMPK-mediated signaling in both muscle and adipocytes. Adipocyte DICER is required for whole-body metabolic adaptations to aerobic exercise training, in part, by allowing controlled substrate utilization in adipose tissue, which, in turn, supports skeletal muscle function. Exercise training increases overall miRNA expression in adipose tissue, and up-regulation of miR-203-3p limits glycolysis in adipose under conditions of metabolic stress. We propose that exercise training-induced DICER-miR-203-3p up-regulation in adipocytes is a key adaptive response that coordinates signals from working muscle to promote whole-body metabolic adaptations.


Assuntos
Tecido Adiposo/metabolismo , RNA Helicases DEAD-box/metabolismo , Exercício Físico/fisiologia , Ribonuclease III/metabolismo , Proteínas Quinases Ativadas por AMP/metabolismo , Adaptação Fisiológica/fisiologia , Adipócitos/metabolismo , Animais , Células Cultivadas , RNA Helicases DEAD-box/deficiência , RNA Helicases DEAD-box/genética , Feminino , Glicólise , Humanos , Masculino , Camundongos , Camundongos Knockout , MicroRNAs/genética , MicroRNAs/metabolismo , Condicionamento Físico Animal , Ribonuclease III/deficiência , Ribonuclease III/genética
15.
PLoS One ; 15(7): e0236702, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32735602

RESUMO

When humans are administered continuous and predictable perturbations of stance, an adaptation period precedes the steady state of balancing behaviour. Little information is available on the modulation of adaptation by vision and perturbation frequency. Moreover, performance of supra-postural tasks may modulate adaptation in as yet unidentified ways. Our purpose was to identify differences in adaptation associated to distinct visual tasks and perturbation frequencies. Twenty non-disabled adult volunteers stood on a platform translating 10 cm in antero-posterior (AP) direction at low (LF, 0.18 Hz) and high frequency (HF, 0.56 Hz) with eyes open (EO) and closed (EC). Additional conditions were reading a text fixed to platform (EO-TP) and reading a text stationary on ground (EO-TG). Peak-to-peak (PP) displacement amplitude and AP position of head and pelvis markers were computed for each of 27 continuous perturbation cycles. The time constant and extent of head and pelvis adaptation and the cross-correlation coefficients between head and pelvis were compared across visual conditions and frequencies. Head and pelvis mean positions in space varied little across conditions and perturbation cycles but the mean head PP displacements changed over time. On average, at LF, the PP displacement of the head and pelvis increased progressively. Adaptation was rapid or ineffective with EO, but slower with EO-TG, EO-TP, EC. At HF, the head PP displacement amplitude decreased progressively with fast adaptation rates, while the pelvis adaptation was not apparent. The results show that visual tasks can modulate the adaptation rate, highlight the effect of the perturbation frequency on adaptation and provide evidence of priority assigned to pelvis stabilization over visual tasks at HF. The effects of perturbation frequency and optic flow and their interaction with other sensory inputs and cognitive tasks on the adaptation strategies should be investigated in impaired individuals and considered in the design of rehabilitation protocols.


Assuntos
Adaptação Fisiológica/fisiologia , Equilíbrio Postural/fisiologia , Percepção Visual/fisiologia , Adulto , Feminino , Humanos , Masculino , Pelve/fisiologia
16.
PLoS One ; 15(8): e0226235, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32797046

RESUMO

Plant-derived fuels and chemicals from renewable biomass have significant potential to replace reliance on petroleum and improve global carbon balance. However, plant biomass contains significant fractions of oligosaccharides that are not usable natively by many industrial microorganisms, including Escherichia coli, Saccharomyces cerevisiae, and Zymomonas mobilis. Even after chemical or enzymatic hydrolysis, some carbohydrate remains as non-metabolizable oligosaccharides (e.g., cellobiose or longer cellulose-derived oligomers), thus reducing the efficiency of conversion to useful products. To begin to address this problem for Z. mobilis, we engineered a strain (Z. mobilis GH3) that expresses a glycosyl hydrolase (GH) with ß-glucosidase activity from a related α-proteobacterial species, Caulobacter crescentus, and subjected it to an adaptation in cellobiose medium. Growth on cellobiose was achieved after a prolonged lag phase in cellobiose medium that induced changes in gene expression and cell composition, including increased expression and extracellular release of GH. These changes were reversible upon growth in glucose-containing medium, meaning they did not result from genetic mutation but could be retained upon transfer of cells to fresh cellobiose medium. After adaptation to cellobiose, our GH-expressing strain was able to convert about 50% of cellobiose to glucose within 24 h and use it for growth and ethanol production. Alternatively, pre-growth of Z. mobilis GH3 in sucrose medium enabled immediate growth on cellobiose. Proteomic analysis of cellobiose- and sucrose-adapted strains revealed upregulation of secretion-, transport-, and outer membrane-related proteins, which may aid release or surface display of GHs, entry of cellobiose into the periplasm, or both. Our two key findings are that Z. mobilis can be reprogrammed to grow on cellobiose as a sole carbon source and that this reprogramming is related to a natural response of Z. mobilis to sucrose that promotes sucrase production.


Assuntos
Celobiose/metabolismo , Zymomonas/crescimento & desenvolvimento , Zymomonas/metabolismo , Adaptação Fisiológica/fisiologia , Biomassa , Reprogramação Celular/genética , Reprogramação Celular/fisiologia , Celulose/metabolismo , Expressão Gênica/genética , Glucose/metabolismo , Hidrolases/metabolismo , Proteômica , Sacarase/metabolismo , Sacarose/metabolismo , Zymomonas/genética , beta-Glucosidase/metabolismo
17.
Nat Commun ; 11(1): 4157, 2020 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-32814767

RESUMO

Swarming is a form of collective bacterial motion enabled by flagella on the surface of semi-solid media. Swarming populations exhibit non-genetic or adaptive resistance to antibiotics, despite sustaining considerable cell death. Here, we show that antibiotic-induced death of a sub-population benefits the swarm by enhancing adaptive resistance in the surviving cells. Killed cells release a resistance-enhancing factor that we identify as AcrA, a periplasmic component of RND efflux pumps. The released AcrA interacts on the surface of live cells with an outer membrane component of the efflux pump, TolC, stimulating drug efflux and inducing expression of other efflux pumps. This phenomenon, which we call 'necrosignaling', exists in other Gram-negative and Gram-positive bacteria and displays species-specificity. Given that adaptive resistance is a known incubator for evolving genetic resistance, our findings might be clinically relevant to the rise of multidrug resistance.


Assuntos
Antibacterianos/metabolismo , Bactérias/metabolismo , Proteínas de Bactérias/metabolismo , Resistência Microbiana a Medicamentos/fisiologia , Transdução de Sinais/fisiologia , Adaptação Fisiológica/fisiologia , Antibacterianos/farmacologia , Bactérias/classificação , Proteínas da Membrana Bacteriana Externa/metabolismo , Bactérias Gram-Negativas/classificação , Bactérias Gram-Negativas/metabolismo , Bactérias Gram-Positivas/classificação , Bactérias Gram-Positivas/metabolismo , Viabilidade Microbiana/efeitos dos fármacos , Periplasma/metabolismo , Especificidade da Espécie
18.
PLoS One ; 15(8): e0237673, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32790747

RESUMO

PURPOSE: This study investigated the acute changes in full spectrum differential blood cell count including reticulocytes and immature reticulocytes after a voluntary maximal dry apnea in non-elite divers. Aim of the present study is to obtain information on important regulatory compensation mechanisms and to provide insights into apneic regulatory processes. METHODS: Ten apnea divers performed a voluntary dry mean apnea time of 317 sec [SD ±111 sec]. Differential blood cell count including reticulocytes was measured before and immediately after a single maximal breath-hold. To evaluate kinetics, blood samples were also taken after 30 min and 4 h. Value distributions are presented with dot plots. P-values were calculated using a mixed linear model for time dependency. Four difference values were compared to baseline values with Dunnett's procedure. RESULTS: Significant changes were found in red blood cell parameters for erythrocytes, red cell distribution width, hematocrit, hemoglobin, MCV, reticulocytes and immature reticulocytes, and in white blood cell parameters for leucocytes, lymphocytes, immature granulocytes, monocytes, basophile granulocytes, neutrophil granulocytes and eosinophil granulocytes and for thrombocytes. CONCLUSION: Adaptive mechanisms regarding cell counts in elite apnea divers are not readily transferable to non-elite recreational sportspersons. Divers and physicians should be aware of the limited adaptive performance of humans in the case of extended apnea.


Assuntos
Adaptação Fisiológica/fisiologia , Suspensão da Respiração , Mergulho/fisiologia , Hipóxia/sangue , Adulto , Contagem de Células Sanguíneas , Hematócrito , Hemoglobinas/análise , Humanos , Hipóxia/fisiopatologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
19.
Am J Physiol Lung Cell Mol Physiol ; 319(3): L456-L470, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32639867

RESUMO

Mechanisms driving adaptive developmental responses to chronic high-altitude (HA) exposure are incompletely known. We developed a novel rat model mimicking the human condition of cardiopulmonary adaptation to HA starting at conception and spanning the in utero and postnatal timeframe. We assessed lung growth and cardiopulmonary structure and function and performed transcriptome analyses to identify mechanisms facilitating developmental adaptations to chronic hypoxia. To generate the model, breeding pairs of Sprague-Dawley rats were exposed to hypobaric hypoxia (equivalent to 9,000 ft elevation). Mating, pregnancy, and delivery occurred in hypoxic conditions. Six weeks postpartum, structural and functional data were collected in the offspring. RNA-Seq was performed on right ventricle (RV) and lung tissue. Age-matched breeding pairs and offspring under room air (RA) conditions served as controls. Hypoxic rats exhibited significantly lower body weights and higher hematocrit levels, alveolar volumes, pulmonary diffusion capacities, RV mass, and RV systolic pressure, as well as increased pulmonary artery remodeling. RNA-Seq analyses revealed multiple differentially expressed genes in lungs and RVs from hypoxic rats. Although there was considerable similarity between hypoxic lungs and RVs compared with RA controls, several upstream regulators unique to lung or RV were identified. We noted a pattern of immune downregulation and regulation patterns of immune and hormonal mediators similar to the genome from patients with pulmonary arterial hypertension. In summary, we developed a novel murine model of chronic hypoxia exposure that demonstrates functional and structural phenotypes similar to human adaptation. We identified transcriptomic alterations that suggest potential mechanisms for adaptation to chronic HA.


Assuntos
Adaptação Fisiológica/fisiologia , Altitude , Hipertensão Pulmonar/fisiopatologia , Hipóxia/fisiopatologia , Transcriptoma/fisiologia , Animais , Modelos Animais de Doenças , Pulmão/fisiopatologia , Ratos Sprague-Dawley , Remodelação Vascular/fisiologia
20.
Am J Physiol Lung Cell Mol Physiol ; 319(2): L360-L368, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32692577

RESUMO

Hypobaric hypoxia poses stress to sojourners traveling to high-altitude. A cascade of physiological changes occurs to cope with or adapt to hypobaric hypoxia. However, an insufficient physiological response to the hypoxic condition resulting from imbalanced vascular homeostasis pathways results in high-altitude pulmonary edema (HAPE). The present study aims to identify the implication of miRNAs associating with HAPE and adaptation. We analyzed the expression of 1,113 miRNAs in HAPE-patients (HAPE-p), HAPE-free controls (HAPE-f), and highland natives (HLs). Based on miRNA profiling and in silico analyses, miR-124-3p emerged relevantly. We observed a significant overexpression of miR-124-3p in HAPE-p. In silico analyses revealed a direct interaction of miR-124-3p with vascular homeostasis and hypoxia-associated genes NOS3 (endothelial nitric oxide synthase), Apelin, and ETS1 (V-Ets avian erythroblastosis virus E2 oncogene homolog 1). Moreover, the transcript and biolevel expression of these genes were significantly decreased in HAPE-p when compared with HAPE-f or HLs. Our in vitro analysis in human umbilical vein endothelial cells demonstrated a significant knockdown of these genes both at transcript and protein levels following miR-124-3p overexpression. Conclusively, our results showed that miR-124-3p might play a plausible role in HAPE pathophysiology by inhibiting the expression of NOS3, Apelin, and ETS1.


Assuntos
Doença da Altitude/sangue , Doença da Altitude/metabolismo , Hipertensão Pulmonar/sangue , Hipertensão Pulmonar/metabolismo , Hipóxia/sangue , Hipóxia/metabolismo , MicroRNAs/sangue , Edema Pulmonar/sangue , Edema Pulmonar/metabolismo , Adaptação Fisiológica/fisiologia , Adulto , Altitude , Apelina/metabolismo , Linhagem Celular , Feminino , Células HEK293 , Células Endoteliais da Veia Umbilical Humana , Humanos , Masculino , Óxido Nítrico Sintase Tipo III/metabolismo , Proteína Proto-Oncogênica c-ets-1/metabolismo , Adulto Jovem
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