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1.
J Endocrinol ; 261(2)2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38470178

RESUMO

For many years, research in the field of steroid synthesis has aimed to understand the regulation of the rate-limiting step of steroid synthesis, i.e. the transport of cholesterol from the outer to the inner mitochondrial membrane, and identify the protein involved in the conversion of cholesterol into pregnenolone. The extraordinary work by B Clark, J Wells, S R King, and D M Stocco eventually identified this protein and named it steroidogenic acute regulatory protein (StAR). The group's finding was also one of the milestones in understanding the mechanism of nonvesicular lipid transport between organelles. A notable feature of StAR is its high degree of phosphorylation. In fact, StAR phosphorylation in the acute phase is required for full steroid biosynthesis. As a contribution to this subject, our work has led to the characterization of StAR as a substrate of kinases and phosphatases and as an integral part of a mitochondrion-associated multiprotein complex, essential for StAR function and cholesterol binding and mitochondrial transport to yield maximum steroid production. Results allow us to postulate the existence of a specific cellular microenvironment where StAR protein synthesis and activation, along with steroid synthesis and secretion, are performed in a compartmentalized manner, at the site of hormone receptor stimulation, and involving the compartmentalized formation of the steroid molecule-synthesizing complex.


Assuntos
Fosfoproteínas , Esteroides , Fosfoproteínas/metabolismo , Colesterol/metabolismo , Microambiente Celular
2.
Sensors (Basel) ; 24(2)2024 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-38257604

RESUMO

Temporal (race) computing schemes rely on temporal memories, where information is represented with the timing of signal edges. Standard digital circuit techniques can be used to capture the relative timing characteristics of signal edges. However, the properties of emerging device technologies could be particularly exploited for more efficient circuit implementations. Specifically, the collective dynamics of networks of memristive devices could be leveraged to facilitate time-domain computations in emerging memristive memories. To this end, this work studies the star interconnect configuration of bipolar memristive devices. Through circuit simulations using a behavioral model of voltage-controlled bipolar memristive devices, we demonstrated the suitability of such circuits in two different contexts, namely sensing and "rank-order" coding. We particularly analyzed the conditions that the employed memristive devices should meet to guarantee the expected operation of the circuit and the possible effects of device variability in the storage and the reproduction of the information in arriving signal edges. The simulation results in LTSpice validate the correct operation and confirm the promising application prospects of such simple circuit structures, which, we show, natively exist in the crossbar geometry. Therefore, the star interconnect configuration could be considered for temporal computations inside resistive memory (ReRAM) arrays.

3.
Entropy (Basel) ; 25(4)2023 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-37190475

RESUMO

In recent years, chaotic synchronization has received a lot of interest in applications in different fields, including in the design of private and secure communication systems. The purpose of this paper was to achieve the synchronization of the Méndez-Arellano-Cruz-Martínez (MACM) 3D chaotic system coupled in star topology. The MACM electronic circuit is used as chaotic nodes in the communication channels to achieve synchronization in the proposed star network; the corresponding electrical hardware in the slave stages receives the coupling signal from the master node. In addition, a novel application to the digital image encryption process is proposed using the coupled-star-network; and the switching parameter technique is finally used to transmit an image as an encrypted message from the master node to the slave coupled nodes. Finally, the cryptosystem is submitted to statistical tests in order to show the effectiveness in multi-user secure image applications.

4.
Front Plant Sci ; 14: 1176701, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37255565

RESUMO

The range of floral colors is determined by the type of plant pigment accumulated by the plant. Anthocyanins are the most common flavonoid pigments in angiosperms; they provide a wide range of visible colors from red-magenta to blue-purple, products of cyanidin and delphinidin biosynthesis, respectively. For the floriculture industry, floral color is one of the most important ornamental characteristics for the development of new commercial varieties; however, most plant species are restricted to a certain color spectrum, limited by their own genetics. In fact, many ornamental crops lack bluish varieties due to the lack of activity of essential biosynthetic enzymes for the accumulation of delphinidin. An example is the poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch), the ornamental plant symbol of Christmas and native to Mexico. Its popularity is the result of the variety of colors displayed by its bracts, a kind of modified leaves that accumulate reddish pigments based mainly on cyanidin and, to a lesser extent, on pelargonidin. The commercial success of this plant lies in the development of new varieties and, although consumers like the typical red color, they are also looking for poinsettias with new and innovative colors. Previous research has demonstrated the possibility of manipulating flower color through metabolic engineering of the anthocyanin biosynthesis pathway and plant tissue culture in different ornamental plant species. For example, transgenic cultivars of flowers such as roses, carnations or chrysanthemums owe their attractive bluish colors to a high and exclusive accumulation of delphinidin. Here, we discuss the possibilities of genetic engineering of the anthocyanin biosynthetic pathway in E. pulcherrima through the introduction of one or more foreign delphinidin biosynthetic genes under the transcriptional control of a pathway-specific promoter, and the genome editing possibilities as an alternative tool to modify the color of the bracts. In addition, some other approaches such as the appropriate selection of the cultivars that presented the most suitable intracellular conditions to accumulate delphinidin, as well as the incorporation of genes encoding anthocyanin-modifying enzymes or transcription factors to favor the bluish pigmentation of the flowers are also revised.

5.
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1441023

RESUMO

ABSTRACT In this study, we report the presence of a female Amblyomma americanum tick attached to a former resident of the East Coast of the United States who moved to Mexico city. The amplification and sequencing of gene fragments of the 16S-rDNA and cytochrome c oxidase subunit 1 corroborated the identification of the species of the tick. Additionally, the presence of DNA of Rickettsia amblyommatis was confirmed. This work is the first report of an exotic tick of the genus Amblyomma in a traveler from the US to Mexico and represents the second record of an imported tick attached to humans in Mexico.

6.
Biology (Basel) ; 11(12)2022 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-36552233

RESUMO

To study how Odontaster validus can influence the spatial structure of Antarctic benthic communities and how they respond to disturbance, it is necessary to assess potential dietary shifts in different habitats. We investigated the diets of O. validus from Maxwell Bay and South Bay in the West Antarctic Peninsula. A multifaceted approach was applied including in situ observations of cardiac stomach everted contents, isotopic niche, and trophic diversity metrics. Results confirm the flexible foraging strategy of this species under markedly different environmental conditions, suggesting plasticity in resource use. The data also showed evidence of isotopic niche expansion, high δ15N values, and Nacella concinna as a common food item for individuals inhabiting a site with low seasonal sea ice (Ardley Cove), which could have significant ecological implications such as new trophic linkages within the Antarctic benthic community. These results highlight the importance of considering trophic changes of key species to their environment as multiple ecological factors can vary as a function of climatic conditions.

7.
J Wound Care ; 31(7): 579-584, 2022 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-35797254

RESUMO

OBJECTIVE: Oncology patients are vulnerable to skin breakdown. The primary purpose of this study was to estimate the prevalence of skin tears (STs) in hospitalised patients with cancer and to explore related sociodemographic and clinical factors. METHOD: This was an observational, epidemiological, cross-sectional study conducted in an oncology hospital in the city of São Paulo. All STs were classified using the STAR Classification adapted and validated for Brazil. RESULTS: Of the 341 patients evaluated, 22 had STs, equating to a prevalence of 6.5%. A higher number of STs were noted on the lower limbs (26.9%) than on other body areas. The main factors associated with STs were the use of anticoagulants, the presence of ecchymosis and the use of incontinence briefs. CONCLUSION: This study contributed to a better understanding of the epidemiology of STs in hospitalised patients with cancer, as well as its associated factors. Results may inform nursing professionals with regard to the need to develop prevention strategies and early interventions.


Assuntos
Lacerações , Neoplasias , Lesões dos Tecidos Moles , Brasil/epidemiologia , Estudos Transversais , Humanos , Lacerações/epidemiologia , Neoplasias/epidemiologia , Prevalência , Pele/lesões
8.
J Biomater Sci Polym Ed ; 33(18): 2353-2384, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35876732

RESUMO

To overcome the disadvantages generated by the lack of interfacial bonding between hydroxyapatite nanocrystals (HAPN) and agglomeration of particles in the development of biodegradable nanocomposites a chemical grafting method was applied to modify the surface of HAPN through grafting of the three-arms star-shaped poly(ε-caprolactone) (SPCL) onto the nanoparticles. The chemical grafting of SPCL onto HAPN (SPCL-g-HAPN) has been investigated using Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy (TEM), photoelectron spectroscopy, X-ray diffraction, zeta potential (ZP) and contact angle (CA). TEM micrographs of the SPCL-g-HAPN revealed the existence of hybrid organic/inorganic (O/I) nanoscale domains. The results of albumin (HSA) and fibrinogen (HFb) adsorption indicate resistance to HFb adsorption by SPCL-g-HAPN relatively to unmodified HAPN. The ZP and CA measurement suggest a heterogeneous topology for SPCL-g-HAPN likely due to the existence of hydrophobic-hydrophilic regions on the nanocomposite surface. The enzyme degradation by cholesterol esterase and lipase indicates that the rates of hydrolysis for SPCL-g-HAPN were very slow relative to the SPCL/HAPN blends. The in vitro biological studies showed that the human osteoblast-like cells (MG-63) cells had normal morphology and they were able to attach and spread out on SPCL-g-HAPN surfaces. A higher overall cellular proliferation was observed on SPCL-g-HAPN scaffolds compared to pure HAPN or SPCL materials.


Assuntos
Caproatos , Poliésteres , Humanos , Poliésteres/química , Lactonas , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície
9.
Semina ciênc. agrar ; 43(3): 973-986, maio.-jun. 2022. graf, tab
Artigo em Inglês | VETINDEX | ID: biblio-1369287

RESUMO

The aim of this study was to evaluate the forage production, nutritional value (including protein fractions), and morphogenic characteristics of African star grass on nitrogen fertilizer in a single application and split applications of two and four, under mob grazing. The study was conducted on a 1.5 ha area with wellestablished African star grass (Cynodon nlemfuensis). The area was divided into 18 paddocks of 400 m2. for three treatments and six replications that were assigned through a randomized block design. The treatments were: Nap1 =Single N application; Nap2= split into two N applications; and Nap4: split into four N applications. Fertilizer application was 200 kg ha-1 of N in topdressing. Pasture was monitored weekly by sward height. Grazing began when the forage reached between 25 and 30 cm in height and ceased at 10 cm. In almost all months evaluated, Nap1 recorded the highest forage production, daily accumulation rate and available forage mass. Some morphogenic characteristics changed between the fertilization strategies, particularly in the months with greater water availability. The chemical composition did not fluctuate between treatments. African star grass can be fertilized with a single application of nitrogen at 200 kg ha-1 to attain greater forage mass and proportion of leaves, without any changes to the chemical composition and nitrogen fractions. These components were modified by the vegetative phase of the forage.(AU)


O objetivo deste estudo foi avaliar a produção de forragem, o valor nutricional, frações protéicas e as características morfogênicas da grama estrela africana estabelecida (Cynodon nlemfuensis) sob adubação nitrogenada parcelada em duas, quatro ou em uma única aplicação. O estudo foi conduzido em uma área de 1,5 ha, que foi dividida em 18 piquetes de 400 m2. O experimento foi delineado estatisticamente em blocos ao acaso, constando de três tratamentos e seis repetições. Os tratamentos corresponderam a aplicação de 200 kg ha-1 de N em cobertura na forma de ureia: Nap1 = aplicação única; Nap2 = parcelado em duas aplicações; e Nap4: parcelado em quatro aplicações. A pastagem foi monitorada semanalmente a partir da medição da altura do pasto. O rebaixamento da pastagem foi realizado por novilhas leiteiras da raça holandesa com 12 meses de idade. Os animais entravam nas parcelas quando a pastagem apresentava altura de 25 a 30 cm e saiam com 10 cm. Em quase todos os meses avaliados, Nap1 apresentou a maior produção de forragem, taxa de acúmulo diário e massa de forragem disponível. Algumas características morfogênicas mudaram entre as estratégias de fertilização, principalmente nos meses de maior disponibilidade hídrica. A composição química não oscilou entre os tratamentos. O capim-estrela africano pode ser fertilizado com uma única aplicação de nitrogênio de 200 kg ha-1 para obter maior quantidade de forragem e proporção de folhas, sem alteração da composição química e das frações do nitrogênio. Esses componentes foram modificados apenas pelo ciclo vegetativo da forragem foram modificados apenas pelo ciclo vegetativo da forragem.(AU)


Assuntos
Pastagens , Cynodon , Morfogênese , Nitrogênio , Valor Nutritivo
10.
Arch. argent. pediatr ; 119(6): e616-e620, dic. 2021. ilus
Artigo em Espanhol | LILACS, BINACIS | ID: biblio-1353046

RESUMO

La neurorretinitis como manifestación de la enfermedad por arañazo de gato se presenta en el 1-2 % de los pacientes con afecciones oculares porBartonella henselae. Las manifestaciones oculares suelen suceder a las sistémicas, aunque pueden aparecer en ausencia de estas. La presencia de exudado macular en forma de estrella es característico y sugestivo de dicha infección. Se presenta el caso de un paciente de 14 años de edad, previamente sano, con disminución de la agudeza visual de 15 días de evolución, que ingresó por sospecha de neuritis óptica izquierda con edema de papila. El seguimiento oftalmológico reveló la aparición de la lesión característica en "estrella macular" que permitió arribar al diagnóstico de infección por B. henselae, confirmándose luego con serología positiva


Neurorretinitis as a manifestation of cat scratch disease occurs in 1-2 % of patients with Bartonella Henselae eye disease. Ocular manifestations tend to follow systemic ones, although they can appear in their absence. The presence of star-shaped macular exudate is characteristic and suggestive of this infection. We report a case of a 14-year-old healthy boy, with 15 days of decreased visual acuity, who was admitted for suspected left optic neuritis with papilledema. Ophthalmological examination revealed the characteristic "macular star" that led to the diagnosis of infection by Bartonella Henselae, later confirmed by positive serology.


Assuntos
Humanos , Masculino , Adolescente , Retinite/diagnóstico , Doença da Arranhadura de Gato/complicações , Doença da Arranhadura de Gato/diagnóstico , Papiledema , Bartonella henselae , Exame Físico
11.
Polymers (Basel) ; 13(21)2021 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-34771233

RESUMO

In this study, six-arm star-shaped poly(N-vinylcaprolactam) (PNVCL) polymers prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization were subjected to aminolysis reaction using hexylamine. Chemically crosslinked gels or highly end-functionalized star polymers can be obtained depending mainly on the type of solvent used during the transformation of the RAFT functional group. An increase in the viscosity of the solution was observed when the aminolysis was carried out in THF. In contrast, when the reaction was conducted in dichloromethane, chain-end thiol (PNVCL)6 star polymers could be obtained. Moreover, when purified (PNVCL-SH)6 star polymers are in contact with THF, the gelation occurs in just a few minutes, with an obvious increase in viscosity, to form physical gels that become chemically crosslinked gels after 12 h. Interestingly, when purified (PNVCL-SH)6 star polymers were stirred in distilled water, even at high aqueous solution concentration (40 mg/mL), there was no increase in the viscosity or gelation, and no evident gels were observed. The analysis of the hydrodynamic diameter (Dh) by dynamic light scattering (DLS) did not detect quantifiable change even after 4 days of stirring in water. On the other hand, the thiol groups in the (PNVCL-SH)6 star polymers were easily transformed into trithiocarbonate groups by addition of CS2 followed by benzyl bromide as demonstrated by UV-Vis spectroscopical analysis and GPC. After the modification, the (PNVCL)6 star polymers exhibit an intense yellow color typical of the absorption band of trithiocarbonate group at 308 nm. To further demonstrate the highly effective new trithiocarbonate end-functionality, the PNVCL polymers were successfully chain extended with N-isopropylacrylamide (NIPAM) to form six-arm star-shaped PNIPAM-b-PNVCL block copolymers. Moreover, the terminal thiol end-functionality in the (PNVCL-SH)6 star polymers was linked via disulfide bond formation to l-cysteine to further demonstrate its reactivity. Zeta potential analysis shows the pH-responsive behavior of these star polymers due to l-cysteine end-functionalization. By this using methodology and properly selecting the solvent, various environment-sensitive star polymers with different end-groups could be easily accessible.

12.
Arch Argent Pediatr ; 119(6): e616-e620, 2021 12.
Artigo em Espanhol | MEDLINE | ID: mdl-34813242

RESUMO

Neurorretinitis as a manifestation of cat scratch disease occurs in 1-2 % of patients with Bartonella Henselae eye disease. Ocular manifestations tend to follow systemic ones, although they can appear in their absence. The presence of star-shaped macular exudate is characteristic and suggestive of this infection. We report a case of a 14-year-old healthy boy, with 15 days of decreased visual acuity, who was admitted for suspected left optic neuritis with papilledema. Ophthalmological examination revealed the characteristic "macular star" that led to the diagnosis of infection by Bartonella Henselae, later confirmed by positive serology.


La neurorretinitis como manifestación de la enfermedad por arañazo de gato se presenta en el 1-2 % de los pacientes con afecciones oculares por Bartonella henselae. Las manifestaciones oculares suelen suceder a las sistémicas, aunque pueden aparecer en ausencia de estas. La presencia de exudado macular en forma de estrella es característico y sugestivo de dicha infección. Se presenta el caso de un paciente de 14 años de edad, previamente sano, con disminución de la agudeza visual de 15 días de evolución, que ingresó por sospecha de neuritis óptica izquierda con edema de papila. El seguimiento oftalmológico reveló la aparición de la lesión característica en "estrella macular" que permitió arribar al diagnóstico de infección por B. henselae, confirmándose luego con serología positiva.


Assuntos
Bartonella henselae , Doença da Arranhadura de Gato , Papiledema , Retinite , Adolescente , Doença da Arranhadura de Gato/complicações , Doença da Arranhadura de Gato/diagnóstico , Humanos , Exame Físico , Retinite/diagnóstico
13.
Proc Biol Sci ; 288(1957): 20211195, 2021 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-34428964

RESUMO

The prevalence of disease-driven mass mortality events is increasing, but our understanding of spatial variation in their magnitude, timing and triggers are often poorly resolved. Here, we use a novel range-wide dataset comprised 48 810 surveys to quantify how sea star wasting disease affected Pycnopodia helianthoides, the sunflower sea star, across its range from Baja California, Mexico to the Aleutian Islands, USA. We found that the outbreak occurred more rapidly, killed a greater percentage of the population and left fewer survivors in the southern half of the species's range. Pycnopodia now appears to be functionally extinct (greater than 99.2% declines) from Baja California, Mexico to Cape Flattery, Washington, USA and exhibited severe declines (greater than 87.8%) from the Salish Sea to the Gulf of Alaska. The importance of temperature in predicting Pycnopodia distribution rose more than fourfold after the outbreak, suggesting latitudinal variation in outbreak severity may stem from an interaction between disease severity and warmer waters. We found no evidence of population recovery in the years since the outbreak. Natural recovery in the southern half of the range is unlikely over the short term. Thus, assisted recovery will probably be required to restore the functional role of this predator on ecologically relevant time scales.


Assuntos
Estrelas-do-Mar , Síndrome de Emaciação , Alaska , Animais , México/epidemiologia , Temperatura
14.
BMC Med Inform Decis Mak ; 21(1): 175, 2021 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-34078366

RESUMO

BACKGROUND: Accurate, comprehensive, cause-specific mortality estimates are crucial for informing public health decision making worldwide. Incorrectly or vaguely assigned deaths, defined as garbage-coded deaths, mask the true cause distribution. The Global Burden of Disease (GBD) study has developed methods to create comparable, timely, cause-specific mortality estimates; an impactful data processing method is the reallocation of garbage-coded deaths to a plausible underlying cause of death. We identify the pattern of garbage-coded deaths in the world and present the methods used to determine their redistribution to generate more plausible cause of death assignments. METHODS: We describe the methods developed for the GBD 2019 study and subsequent iterations to redistribute garbage-coded deaths in vital registration data to plausible underlying causes. These methods include analysis of multiple cause data, negative correlation, impairment, and proportional redistribution. We classify garbage codes into classes according to the level of specificity of the reported cause of death (CoD) and capture trends in the global pattern of proportion of garbage-coded deaths, disaggregated by these classes, and the relationship between this proportion and the Socio-Demographic Index. We examine the relative importance of the top four garbage codes by age and sex and demonstrate the impact of redistribution on the annual GBD CoD rankings. RESULTS: The proportion of least-specific (class 1 and 2) garbage-coded deaths ranged from 3.7% of all vital registration deaths to 67.3% in 2015, and the age-standardized proportion had an overall negative association with the Socio-Demographic Index. When broken down by age and sex, the category for unspecified lower respiratory infections was responsible for nearly 30% of garbage-coded deaths in those under 1 year of age for both sexes, representing the largest proportion of garbage codes for that age group. We show how the cause distribution by number of deaths changes before and after redistribution for four countries: Brazil, the United States, Japan, and France, highlighting the necessity of accounting for garbage-coded deaths in the GBD. CONCLUSIONS: We provide a detailed description of redistribution methods developed for CoD data in the GBD; these methods represent an overall improvement in empiricism compared to past reliance on a priori knowledge.


Assuntos
Confiabilidade dos Dados , Saúde Global , Algoritmos , Brasil , Causas de Morte , Feminino , França , Humanos , Japão , Masculino
15.
Sensors (Basel) ; 21(3)2021 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-33572822

RESUMO

Developing star trackers quickly is non-trivial. Achieving reproducible results and comparing different algorithms are also open problems. In this sense, this work proposes the use of synthetic star images (a simulated sky), allied with the standardized structure of the Universal Verification Methodology as the base of a design approach. The aim is to organize the project, speed up the development time by providing a standard verification methodology. Future rework is reduced through two methods: a verification platform that us shared under a free software licence; and the layout of Universal Verification Methodology enforces reusability of code through an object-oriented approach. We propose a black-box structure for the verification platform with standard interfaces, and provide examples showing how this approach can be applied to the development of a star tracker for small satellites, targeting a system-on-a-chip design. The same test benches were applied to both early conceptual software-only implementations, and later optimized software-hardware hybrid systems, in a hardware-in-the-loop configuration. This test bench reuse strategy was interesting also to show the regression test capability of the developed platform. Furthermore, the simulator was used to inject specific noise, in order to evaluate the system under some real-world conditions.

16.
Chemosphere ; 263: 128016, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297042

RESUMO

Benzo(a)pyrene (BaP) is a persistent organic pollutant and endocrine disruptor that can compromise the steroidogenesis process by interacting with the StAR protein, causing adverse effects on male reproduction. However, consequences of prepubertal BaP exposure and its impacts on adult life are yet unknown. This study investigated the effects of BaP exposure from the juvenile period to peripubertal on reproductive parameters in adult male rats. Males were exposed to 0; 0.1; 1 or 10 µg/kg/day of BaP from post-natal (PND) 23 to PND 53 (by gavage). The lowest dose of BaP was able to compromise the male copulatory behavior, as evidenced by the delay in the first mount, intromission and ejaculation. Furthermore, BaP-treated groups showed lower sperm quality (disrupted motility and morphology) and quantity, reduced relative weights of the thyroid and seminal gland. Serum testosterone levels and the Leydig cells nuclei volume were decreased by BaP exposure whereas the StAR expression was increased. Histopathological changes in the testis also were detected in the males exposed to BaP. These results showed that prepubertal BaP-exposure adversely influenced the male reproductive system in the adult life, indicating that a comprehensive risk assessment of BaP-exposure on prepubertal period is necessary.


Assuntos
Benzo(a)pireno , Disruptores Endócrinos , Animais , Benzo(a)pireno/toxicidade , Disruptores Endócrinos/toxicidade , Masculino , Ratos , Reprodução , Espermatozoides , Testículo
17.
J Steroid Biochem Mol Biol ; 208: 105792, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33246155

RESUMO

Acyl-CoA synthetase 4 (Acsl4), an enzyme involved in arachidonic acid (AA) metabolism, participates in physiological and pathological processes such as steroidogenesis and cancer. The role of Acsl4 in neurons and in nervous system development has also been documented but little is known regarding its functionality in glial cells. In turn, several processes in glial cells, including neurosteroidogenesis, stellation and AA uptake, are regulated by cyclic adenosine monophosphate (cAMP) signal. In this context, the aim of this work was to analyze the expression and functional role of Acsl4 in primary rat astrocyte cultures and in the C6 glioma cell line by chemical inhibition and stable silencing, respectively. Results show that Acsl4 expression was regulated by cAMP in both models and that cAMP stimulation of steroidogenic acute regulatory protein mRNA levels was reduced by Acsl4 inhibition or silencing. Also, Acsl4 inhibition reduced progesterone synthesis stimulated by cAMP and also affected cAMP-induced astrocyte stellation, decreasing process elongation and increasing branching complexity. Similar effects were observed for Acsl4 silencing on cAMP-induced C6 cell morphological shift. Moreover, Acsl4 inhibition and silencing reduced proliferation and migration of both cell types. Acsl4 silencing in C6 cells reduced the capacity for colony proliferation and neurosphere formation, the latter ability also being abolished by Acsl4 inhibition. In sum, this work presents novel evidence of Acsl4 involvement in neurosteroidogenesis and the morphological changes of glial cells promoted by cAMP. Furthermore, Acsl4 participates in migration and proliferation, also affecting cell self-renewal. Altogether, these findings provide insights into Acsl4 functions in glial cells.


Assuntos
Ácido Araquidônico/genética , Coenzima A Ligases/genética , Neuroglia/metabolismo , Animais , Ácido Araquidônico/metabolismo , Astrócitos/metabolismo , Astrócitos/patologia , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Coenzima A Ligases/metabolismo , AMP Cíclico/genética , Regulação Neoplásica da Expressão Gênica/genética , Glioma/genética , Glioma/patologia , Humanos , Neuroglia/patologia , Ratos
18.
Rev. biol. trop ; Rev. biol. trop;69(1)2021.
Artigo em Inglês | LILACS, SaludCR | ID: biblio-1507817

RESUMO

Introduction: The Panamic Cushion Star Pentaceraster cumingi is widely distributed along the Tropical Eastern Pacific. This species strictly produces only five arms, but sometimes, this number varies or show another kind of abnormality. Objective: We aimed to evaluate the population size structure and abnormalities occurrence in the radial pattern of P. cumingi in Bahía Chamela, Jalisco, Mexico. Methods: The population was monitored along four years (2016-2019), in two seasonal periods (warm and cold). During fieldwork, a random sample of individuals was collected. Every starfish was measured, weighted, and evaluated to identify any abnormality on its radial pattern. Results: The highest density of P. cumingi was found in October 2019 (2.03 ± 0.05 ind/m-2), the lower in March 2017 (0.66 ± 0.13 ind/m-2). A total of 849 individuals were collected. For 5-armed starfishes, the average length was 123.8 ± 15.2 mm and the average weight of 326.0 ± 62.4 g. The most frequent length classes ranged from 110 to 120 mm. Of the total of individuals sampled 0.82 % had four arms, 1.06 % six, and 1.41 % had one bifurcated arm. Conclusions: There were differences in the population density and size structure of P. cumingi between seasons. The main causes of abnormalities in the starfish could be due to the changes that occur during larval metamorphosis or by an abnormal regeneration of the arms after a predation attempt.


Introducción: La Estrella Cojín Pentaceraster cumingi está ampliamente distribuida a lo largo del Pacífico Oriental Tropical. Esta especie produce estrictamente cinco brazos, pero en algunas ocasiones el número puede ser menor o mayor de cinco, o mostrar otro tipo de anormalidad. Objetivo: Evaluar la estructura de tallas poblacional y la presencia de anormalidades en el patrón radial de P. cumingi en la Bahía Chamela, Jalisco, México. Métodos: La población fue monitoreada a lo largo de cuatro años (2016-2019), durante dos periodos estacionales (cálido y templado). Durante el trabajo de campo se recolectó una muestra aleatoria de individuos. Cada estrella de mar fue medida, pesada y revisada para identificar alguna anormalidad en el patrón radial. Resultados: La mayor densidad de individuos se encontró en octubre de 2019 (2.03 ± 0.05 ind/m-2), la menor en marzo de 2017 (0.66 ± 0.13 ind/m-2). Un total de 849 individuos fueron recolectados. Para las estrellas de mar con 5 brazos, la longitud promedio fue de 123.8 ± 15.2 mm y el peso promedio de 326.0 ± 62.4 g. La clase de talla más frecuente varió entre 110 y 120 mm. Del total de individuos muestreados el 0.82 % tuvieron cuatro brazos, el 1.06 % con seis, y el 1.41 % tuvieron un brazo bifurcado. Conclusiones: Se encontraron diferencias en la densidad poblacional y en la estructura de tallas de P. cumingi entre estaciones. Las principales causas de anormalidades en la estrella de mar pueden ser debidas a los cambios que ocurren durante la metamorfosis de las larvas o por una regeneración anormal de los brazos a causa de la depredación.


Assuntos
Animais , Estrelas-do-Mar/crescimento & desenvolvimento , Ecossistema , Equinodermos/anatomia & histologia , México
19.
Front Vet Sci ; 7: 586265, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33195615

RESUMO

The beta-nerve growth factor (ß-NGF) from llama seminal plasma exerts ovulatory and luteotrophic effects following intramuscular or intrauterine infusion in llamas and alpacas. In this study, we investigate the in vitro effect of llama ß-NGF on the expression of genes involved in angiogenesis and progesterone synthesis as well as progesterone release in preovulatory llama granulosa cells; we also determine whether these changes are mediated via the ERK1/2 signaling pathway. From adult female llamas, we collected granulosa cells from preovulatory follicles by transvaginal ultrasound-guided follicle aspiration; these cells were pooled and incubated. After 80% confluence, the cultured granulosa cells were treated with ß-NGF, ß-NGF plus the MAPK inhibitor U0126, or luteinizing hormone, and the abundance of angiogenic and steroidogenic enzyme mRNA transcripts were quantified after 10 and 20 h by RT-qPCR. We also quantified the progesterone concentration in the media after 48 h by radioimmunoassay. We found that application of ß-NGF increases the abundance of mRNA transcripts of the vascular endothelial growth factor (VEGFA) and the steroidogenic enzymes cytochrome P450 side-chain cleavage (P450scc/CYP11A1), steroidogenic acute regulatory protein (STAR), and 3ß-hydroxysteroid dehydrogenase (HSD3B1) at 10 and 20 h of treatment. Application of the MAPK inhibitor U0126 resulted in downregulation of the genes encoding these enzymes. ß-NGF also enhanced progesterone synthesis, which was prevented by the prior application of the MAPK inhibitor U0126. Finally, western blot analysis confirmed that ß-NGF activates the ERK1/2 signaling pathway. In conclusion, our results indicate that ß-NGF exerts direct luteotropic effects on llama ovarian tissue via the ERK 1/2 pathway.

20.
Heliyon ; 6(2): e03342, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32099915

RESUMO

Indices improve the performance of relational databases, especially on queries that return a small portion of the data (i.e., low-selectivity queries). Star joins are particularly expensive operations that commonly rely on indices for improved performance at scale. The development and support of index-based solutions for Star Joins are still at very early stages. To address this gap, we propose a distributed Bitmap Join Index (dBJI) and a framework-agnostic strategy to solve join predicates in linear time. For empirical analysis, we used common Hadoop technologies (e.g., HBase and Spark) to show that dBJI significantly outperforms full scan approaches by a factor between 59% and 88% in queries with low selectivity from the Star Schema Benchmark (SSB). Thus, distributed indices may significantly enhance low-selectivity query performance even in very large databases.

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