scispace - formally typeset
Search or ask a question
Author

Bruno Ramos

Other affiliations: Tokyo Institute of Technology
Bio: Bruno Ramos is an academic researcher from University of São Paulo. The author has contributed to research in topics: Photocatalysis & Microreactor. The author has an hindex of 9, co-authored 22 publications receiving 184 citations. Previous affiliations of Bruno Ramos include Tokyo Institute of Technology.

Papers
More filters
Journal ArticleDOI
03 Sep 2014-PLOS ONE
TL;DR: The results suggest that melanopsin may be important in mediating the photoresponse in Danio rerio ZEM-2S cells, and provide new insights about the modulation of clock genes in peripheral clocks.
Abstract: Melanopsin has been implicated in the mammalian photoentrainment by blue light. This photopigment, which maximally absorbs light at wavelengths between 470 and 480 nm depending on the species, is found in the retina of all classes of vertebrates so far studied. In mammals, melanopsin activation triggers a signaling pathway which resets the circadian clock in the suprachiasmatic nucleus (SCN). Unlike mammals, Drosophila melanogaster and Danio rerio do not rely only on their eyes to perceive light, in fact their whole body may be capable of detecting light and entraining their circadian clock. Melanopsin, teleost multiple tissue (tmt) opsin and others such as neuropsin and va-opsin, are found in the peripheral tissues of Danio rerio, however, there are limited data concerning the photopigment/s or the signaling pathway/s directly involved in light detection. Here, we demonstrate that melanopsin is a strong candidate to mediate synchronization of zebrafish cells. The deduced amino acid sequence of melanopsin, although being a vertebrate opsin, is more similar to invertebrate than vertebrate photopigments, and melanopsin photostimulation triggers the phosphoinositide pathway through activation of a Gq/11-type G protein. We stimulated cultured ZEM-2S cells with blue light at wavelengths consistent with melanopsin maximal absorption, and evaluated the time course expression of per1b, cry1b, per2 and cry1a. Using quantitative PCR, we showed that blue light is capable of slightly modulating per1b and cry1b genes, and drastically increasing per2 and cry1a expression. Pharmacological assays indicated that per2 and cry1a responses to blue light are evoked through the activation of the phosphoinositide pathway, which crosstalks with nitric oxide (NO) and mitogen activated protein MAP kinase (MAPK) to activate the clock genes. Our results suggest that melanopsin may be important in mediating the photoresponse in Danio rerio ZEM-2S cells, and provide new insights about the modulation of clock genes in peripheral clocks.

31 citations

Journal ArticleDOI
30 Dec 2015
TL;DR: The present review brings some evidence of how these programs may have co-evolved in systems able to deal with 2 or more environmental clues, and how they similarly function in different group of animals, stressing how important temperature and light were to establish the temporal organizations.
Abstract: Circadian rhythm may be understood as a temporal organization that works to orchestrate physiological processes and behavior in a period of approximately 24 h. Because such temporal organization has evolved in the presence of predictable environmental clues, such as day length, tides, seasons, and temperature, the organism has confronted the natural selection in highly precise intervals of opportunities and risks, generating temporal programs and resetting mechanisms, which are well conserved among different taxa of animals. The present review brings some evidence of how these programs may have co-evolved in systems able to deal with 2 or more environmental clues, and how they similarly function in different group of animals, stressing how important temperature and light were to establish the temporal organizations. For example, melanopsin and rhodopsin, photopigments present respectively in circadian and visual photoreceptors, are required for temperature discrimination in Drosophila melanogaster. These ...

30 citations

Journal ArticleDOI
TL;DR: In this paper, the feasibility of using flexible polymer microtubes as photocatalyst supports was investigated by using PFA tubes of various inner diameters (i.e., i.d.).
Abstract: The feasibility of using flexible polymer microtubes as photocatalyst supports was investigated by using PFA tubes of various inner diameters (i.d.). Catalyst immobilisation was performed by loading a prepared TiO 2 suspension into the tubes, which were then subjected to a quick thermal treatment at 285 °C. The presence of the catalyst on the inner walls of the tubes was confirmed by SEM-EDS analysis, and the thicknesses of the resulting catalytic layers were evaluated by SEM for different catalyst precursor concentrations. The performances of the reactors were investigated by the photocatalytic degradation of phenol. The apparent reaction rates observed on these reactors were found to be one order of magnitude larger than found in a small batch vessel operating with suspended slurry. The effects of the number of catalytic coatings, the concentration of the catalyst precursor suspension, the reactor inner diameter and the initial pH of the solutions on the performance of the reactor were investigated.

22 citations

Journal ArticleDOI
TL;DR: The results open a novel investigative perspective regarding the relationship between temperature and clock genes, placing a new player in the regulation of this phenomenon: the TRPV1 channel.

18 citations

Journal ArticleDOI
TL;DR: X. laevis melanophores, which have already led to melanopsin discovery, represent an ideal model to understanding circadian rhythms and add an important contribution to the emerging field of peripheral clocks, which in nonmammalian vertebrates have been mostly studied in Drosophila and Danio rerio.
Abstract: Light-dark cycles are considered important cues to entrain biological clocks. A feedback loop of clock gene transcription and translation is the molecular basis underlying the mechanism of both central and peripheral clocks. Xenopus laevis embryonic melanophores respond to light with melanin granule dispersion, response possibly mediated by the photopigment melanopsin. In order to test whether light modulates clock gene expression in Xenopus melanophores, we used qPCR to evaluate the relative mRNA levels of Per1, Per2, Clock and Bmal1 in cultured melanophores exposed to light-dark (LD) cycle or constant darkness (DD). LD cycles elicited temporal changes in the expression of Per1, Per2 and Bmal1. A 10-min pulse of blue light was able to increase the expression of Per1 and Per2. Red light had no effect on the expression of these clock genes. These data suggest the participation of a blue-wavelength sensitive pigment in the light-dark cycle-mediated oscillation of the endogenous clock. Our results add an important contribution to the emerging field of peripheral clocks, which in non-mammalian vertebrates have been mostly studied in Drosophila and Danio rerio. Within this context, we show that Xenopus laevis melanophores, which have already led to melanopsin discovery, represent an ideal model to understanding circadian rhythms. This article is protected by copyright. All rights reserved.

16 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: In this review, an up-to-date overview is given of photochemical transformations in continuous-flow reactors, including applications in organic synthesis, material science, and water treatment.
Abstract: Continuous-flow photochemistry in microreactors receives a lot of attention from researchers in academia and industry as this technology provides reduced reaction times, higher selectivities, straightforward scalability, and the possibility to safely use hazardous intermediates and gaseous reactants. In this review, an up-to-date overview is given of photochemical transformations in continuous-flow reactors, including applications in organic synthesis, material science, and water treatment. In addition, the advantages of continuous-flow photochemistry are pointed out and a thorough comparison with batch processing is presented.

1,027 citations

Journal Article
TL;DR: In this article, the authors highlight recent advances in understanding of the core molecular clock and how it utilizes diverse transcriptional and post-transcriptional mechanisms to impart temporal control onto mammalian physiology.
Abstract: Circadian clocks coordinate physiology and behavior with the 24h solar day to provide temporal homeostasis with the external environment. The molecular clocks that drive these intrinsic rhythmic changes are based on interlocked transcription/translation feedback loops that integrate with diverse environmental and metabolic stimuli to generate internal 24h timing. In this review we highlight recent advances in our understanding of the core molecular clock and how it utilizes diverse transcriptional and post-transcriptional mechanisms to impart temporal control onto mammalian physiology. Understanding the way in which biological rhythms are generated throughout the body may provide avenues for temporally directed therapeutics to improve health and prevent disease.

702 citations

Journal ArticleDOI
15 May 2017
TL;DR: One of the most reproducible effects of PBM is an overall reduction in inflammation, which is particularly important for disorders of the joints, traumatic injuries, lung disorders, and in the brain.
Abstract: Photobiomodulation (PBM) also known as low-level level laser therapy is the use of red and near-infrared light to stimulate healing, relieve pain, and reduce inflammation The primary chromophores have been identified as cytochrome c oxidase in mitochondria, and calcium ion channels (possibly mediated by light absorption by opsins) Secondary effects of photon absorption include increases in ATP, a brief burst of reactive oxygen species, an increase in nitric oxide, and modulation of calcium levels Tertiary effects include activation of a wide range of transcription factors leading to improved cell survival, increased proliferation and migration, and new protein synthesis There is a pronounced biphasic dose response whereby low levels of light have stimulating effects, while high levels of light have inhibitory effects It has been found that PBM can produce ROS in normal cells, but when used in oxidatively stressed cells or in animal models of disease, ROS levels are lowered PBM is able to up-regulate anti-oxidant defenses and reduce oxidative stress It was shown that PBM can activate NF-kB in normal quiescent cells, however in activated inflammatory cells, inflammatory markers were decreased One of the most reproducible effects of PBM is an overall reduction in inflammation, which is particularly important for disorders of the joints, traumatic injuries, lung disorders, and in the brain PBM has been shown to reduce markers of M1 phenotype in activated macrophages Many reports have shown reductions in reactive nitrogen species and prostaglandins in various animal models PBM can reduce inflammation in the brain, abdominal fat, wounds, lungs, spinal cord

497 citations

Journal ArticleDOI
TL;DR: The redox signaling that occurs in PBM is covered and the difference between healthy and stressed cells is examined, where PBM can have apparently opposite effects.
Abstract: Photobiomodulation (PBM) involves the use of red or near-infrared light at low power densities to produce a beneficial effect on cells or tissues. PBM therapy is used to reduce pain, inflammation, edema, and to regenerate damaged tissues such as wounds, bones, and tendons. The primary site of light absorption in mammalian cells has been identified as the mitochondria and, more specifically, cytochrome c oxidase (CCO). It is hypothesized that inhibitory nitric oxide can be dissociated from CCO, thus restoring electron transport and increasing mitochondrial membrane potential. Another mechanism involves activation of light or heat-gated ion channels. This review will cover the redox signaling that occurs in PBM and examine the difference between healthy and stressed cells, where PBM can have apparently opposite effects. PBM has a marked effect on stem cells, and this is proposed to operate via mitochondrial redox signaling. PBM can act as a preconditioning regimen and can interact with exercise on muscles.

331 citations

Journal ArticleDOI
TL;DR: This review summarized the synchronizers and the synchronization methods used in experimental research, and introduced CR monitoring and detection methods, and evaluated conventional CR databases and analyzed experiments that characterized the underlying causes of CR disorder.
Abstract: Circadian rhythms (CR) are a series of endogenous autonomous oscillators generated by the molecular circadian clock which acting on coordinating internal time with the external environment in a 24-h daily cycle. The circadian clock system is a major regulatory factor for nearly all physiological activities and its disorder has severe consequences on human health. CR disruption is a common issue in modern society, and researches about people with jet lag or shift works have revealed that CR disruption can cause cognitive impairment, psychiatric illness, metabolic syndrome, dysplasia, and cancer. In this review, we summarized the synchronizers and the synchronization methods used in experimental research, and introduced CR monitoring and detection methods. Moreover, we evaluated conventional CR databases, and analyzed experiments that characterized the underlying causes of CR disorder. Finally, we further discussed the latest developments in understanding of CR disruption, and how it may be relevant to health and disease. Briefly, this review aimed to synthesize previous studies to aid in future studies of CR and CR-related diseases.

139 citations