Photobiomodulation therapy and NMES improve muscle strength and jumping performance in young volleyball athletes: a randomized controlled trial study in Brazil.

The purpose of this study was to investigate the effectiveness of adding photobiomodulation therapy and neuromuscular electrical stimulation (NMES) to volleyball athletes' training, focusing on muscle strength and jumping skills. Thirty-six athletes were randomly placed into three groups: control, photobiomodulation therapy, and NMES. The athletes trained to improve their muscle strength and jumping skills. The athletes in the photobiomodulation therapy group were submitted to photobiomodulation therapy (850 nm, continuous, energy density 0.8 J/cm2, radiant energy per point 6 J, total radiant energy 36 J) before undergoing strength and plyometric training. The NMES group additionally underwent NMES-based quadriceps femoris muscle strength training (base frequency 1 kHz, frequency modulation 70 Hz, intensity maximum tolerable). The variables analyzed were muscle strength, jumping ability, global impression, and jump frequency; they were measured at baseline and during follow-ups at 6 and 8 weeks. The statistical analysis was conducted on an intention-to-treat basis. The between-group differences and their respective 95% CIs were calculated using linear mixed models by using group, time, and group-versus-time interaction terms. Dominant lower limb strength improved the most in the NMES group compared to the control group (mean difference = 1.4, 95% CI = .5 to 2.4). Non-dominant lower limb strength increased in both the photobiomodulation therapy group (mean difference = 1.1, 95% CI = .3 to 2) and the NMES group (mean difference = 1.9, 95% CI = 1.1 to 2.8) compared to the control group, but the NMES group improved more than the photobiomodulation therapy group (mean difference = 0.8, 95% CI = 0.1 to 1.7). The NMES group had the greatest improvement in global perceived effect scale compared to the control group (mean difference = 1.1, 95% CI = 1 to 2.2). Dominant lower limb strength improved in the NMES group compared to the control group. Non-dominant lower limb strength increased in both the photobiomodulation therapy group and the NMES group compared to the control group, but the NMES group improved significantly more than the photobiomodulation therapy group; the NMES group also improved in the global perceived effect scale compared to the control group. This study found that, for volleyball athletes, photobiomodulation therapy and NMES both promoted benefits in terms of muscle-strength gain. In addition, these benefits were maintained for 2 weeks even after training was interrupted. Dominant lower limb strength improved in the NMES group compared to the control group. Non-dominant lower limb strength increased in both the photobiomodulation therapy group and the NMES group compared to the control group, but the NMES group improved significantly more than the photobiomodulation therapy group; the NMES group also improved in global impression of jumps compared to the control group.

Artificial light pollution at night (ALAN) disrupts the distribution and circadian rhythm of a sandy beach isopod.

Coastal habitats, in particular sandy beaches, are becoming increasingly exposed to artificial light pollution at night (ALAN). Yet, only a few studies have this far assessed the effects of ALAN on the species inhabiting these ecosystems. In this study we assessed the effects of ALAN on Tylos spinulosus, a prominent wrack-consumer isopod living in sandy beaches of north-central Chile. This species burrows in the sand during daylight and emerges at night to migrate down-shore, so we argue it can be used as a model species for the study of ALAN effects on coastal nocturnal species. We assessed whether ALAN alters the distribution and locomotor activity of this isopod using a light system placed in upper shore sediments close to the edge of the dunes, mimicking light intensities measured near public lighting. The response of the isopods was compared to control transects located farther away and not exposed to artificial light. In parallel, we measured the isopods' locomotor activity in the laboratory using actographs that recorded their movement within mesocosms simulating the beach surface. Measurements in the field indicated a clear reduction in isopod abundance near the source of the light and a restriction of their tidal distribution range, as compared to control transects. Meanwhile, the laboratory experiments showed that in mesocosms exposed to ALAN, isopods exhibited reduced activity and a circadian rhythm that was altered and even lost after a few days. Such changes with respect to control mesocosms with a natural day/night cycle suggest that the changes observed in the field were directly related to a disruption in the locomotor activity of the isopods. All together these results provide causal evidence of negative ALAN effects on this species, and call for further research on other nocturnal sandy beach species that might become increasingly affected by ALAN.

Sunlight-induced genotoxicity and damage in keratin structures decrease tadpole performance.

The increased incidence of solar ultraviolet (UV) radiation, an environmental genotoxic agent, due to ozone depletion or deforestation may help to explain the enigmatic decline of amphibian populations in specific localities. In this work, we evaluated the importance of DNA repair performed by photolyases to maintain the performance of treefrog tadpoles after acute and chronic treatments with environmental-simulated doses of solar UVB and UVA radiation. Immediately after UV treatments, tadpoles were exposed to a visible light source to activate photolyases or kept in dark containers. The biological effects of UV treatments were evaluated through morphological, histological, locomotor and survival analyzes of Boana pulchella tadpoles (Anura: Hylidae). The results indicate that tadpole body weight suffered influence after both UVB and UVA treatments, although the body length was bit affected. The locomotor performance of UVB-exposed tadpoles was significantly reduced. In addition, UVB radiation induced a severe impact on tadpole skin, as well as on keratinized structures of mouth (tooth rows and jaw), indicating that these should be important effects of solar UV radiation in the reduction of tadpole performance. Furthermore, photolyases activation was fundamental for the maintenance of tadpole performance after chronic UVB exposures, but it was relatively inefficient after acute exposures to UVB, but not to UVA radiation. Therefore, this work demonstrates how the UV-induced genotoxicity and structural alterations in the skin and oral apparatus affect tadpole performance and survival.

Effects of repeated 9 and 30-day exposure to extremely low-frequency electromagnetic fields on social recognition behavior and estrogen receptors expression in olfactory bulb of Wistar female rats.

OBJECTIVE: We investigated the short- and long-term effects of extremely low-frequency electromagnetic fields (EMF) on social recognition behavior and expression of α- and ß-estrogen receptors (ER). METHODS: Rats were exposed to 60-Hz electromagnetic fields for 9 or 30 days and tested for social recognition behavior. Immunohistochemistry and western blot assays were performed to evaluate α- and ß-ER expression in the olfactory bulb of intact, ovariectomized (OVX), and ovariectomized+estradiol (E2) replacement (OVX+E2). RESULTS: Ovariectomization showed impairment of social recognition after 9 days of EMF exposure and a complete recovery after E2 replacement and so did those after 30 days. Short EMF exposure increased expression of ß-ER in intact, but not in the others. Longer exposure produced a decrease in intact but an increase in OVX and OVX+E2. DISCUSSION: Our findings suggest a significant role for ß-estrogen receptors and a lack of effect for α-estrogen receptors on a social recognition task. ABBREVIATIONS: EMF: extremely low frequency electromagnetic fields; ERs: estrogen receptors; OB: olfactory bulb; OVX: ovariectomized; OVX + E2: ovariectomized + estradiol replacement; IEI: interexposure interval; ß-ER: beta estrogen receptor; E2: replacement of estradiol; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; WB: Western blot; PBS: phosphate-buffer saline; PB: phosphate-buffer.

Synchronization to light and mealtime of the circadian rhythms of self-feeding behavior and locomotor activity of white shrimps (Litopenaeus vannamei).

The role of light and feeding cycles in synchronizing self-feeding and locomotor activity rhythms was studied in white shrimps using a new self-feeding system activated by photocell trigger. In experiment 1, shrimps maintained under a 12:12h light/dark (LD) photoperiod were allowed to self-feed using feeders connected to a photoelectric cell, while locomotor activity was recorded with a second photocell. On day 30, animals were subjected to constant darkness (DD) for 12days to check the existence of endogenous circadian rhythms. In the experiment 2, shrimps were exposed to both a 12:12h LD photoperiod and a fixed meal schedule in the middle of the dark period (MD, 01:00h). On day 20, shrimps were exposed to DD conditions and the same fixed feeding. On day 30, they were maintained under DD and fasted for 7days. The results revealed that under LD, shrimps showed a clear nocturnal feeding pattern and locomotor activity (81.9% and 67.7% of total daily food-demands and locomotor activity, respectively, at nighttime). Both feeding and locomotor rhythms were endogenously driven and persisted under DD with an average period length (τ) close to 24h (circadian) (τ=24.18±0.13 and 23.87±0.14h for locomotor and feeding, respectively). Moreover, Shrimp showed a daily food intake under LD condition (1.1±0.2gday(-1) in the night phase vs. 0.2±0.1gday(-1) in the light phase). Our findings might be relevant for some important shrimp aquaculture aspects, such as developing suitable feeding management on shrimp farms.

Photokinesis is magnetic field dependent in the multicellular magnetotactic prokaryote Candidatus Magnetoglobus multicellularis.

Candidatus Magnetoglobus multicellularis is a spherical, multicellular, magnetotactic prokaryote (MMP) composed of 10-40 genetically-identical, Gram-negative cells. It is known that monochromatic light of low intensity influences its average swimming velocity, being higher for red light (628 nm) and lower for green light (517 nm). In this study, we determined the effect of light of different wavelengths and intensities on the swimming velocity of Ca. Magnetoglobus multicellularis under different magnetic field intensities. The swimming velocities of several organisms exposed to blue light (469 nm), green light (517 nm) and red light (628 nm) with intensities ranging from 0.36 to 3.68 Wm(-2) were recorded under magnetic field intensities ranging from 0.26 to 1.47 Oe. Our results showed that MMPs exposed to green light display consistently lower average swimming velocities compared to other wavelengths of light. We also show for the first time that photokinesis in Ca. Magnetoglobus multicellularis is dependent on the magnetic field being applied. The relationship between light wavelength and intensity and magnetic field strength and swimming velocity in this MMP is therefore complex. Although the mechanism for the observed behaviour is not completely understood, a flavin-containing chromophore may be involved.

Effect of light wavelength on motility and magnetic sensibility of the magnetotactic multicellular prokaryote 'Candidatus Magnetoglobus multicellularis'.

'Candidatus Magnetoglobus multicellularis' is a magnetotactic microorganism composed of several bacterial cells. Presently, it is the best known multicellular magnetotactic prokaryote (MMP). Recently, it has been observed that MMPs present a negative photoresponse to high intensity ultraviolet and violet-blue light. In this work, we studied the movement of 'Candidatus Magnetoglobus multicellularis' under low intensity light of different wavelengths, measuring the average velocity and the time to reorient its trajectory when the external magnetic field changes its direction (U-turn time). Our results show that the mean average velocity is higher for red light (628 nm) and lower for green light (517 nm) as compared to yellow (596 nm) and blue (469 nm) light, and the U-turn time decreased for green light illumination. The light wavelength velocity dependence can be understood as variation in flagella rotation speed, being increased by the red light and decreased by the green light relative to yellow and blue light. It is suggested that the dependence of the U-turn time on light wavelength can be considered a form of light-dependent magnetotaxis, because this time represents the magnetic sensibility of the magnetotactic microorganisms. The cellular and molecular mechanisms for this light-dependent velocity and magnetotaxis are unknown and deserve further studies to understand the biochemical interactions and the ecological roles of the different mechanisms of taxis in MMPs.

Swimming behaviour of the multicellular magnetotactic prokaryote 'Candidatus Magnetoglobus multicellularis' under applied magnetic fields and ultraviolet light.

Magnetotactic bacteria move by rotating their flagella and concomitantly are aligned to magnetic fields because they present magnetosomes, which are intracellular organelles composed by membrane-bound magnetic crystals. This results in magnetotaxis, which is swimming along magnetic field lines. Magnetotactic bacteria are morphologically diverse, including cocci, rods, spirilla and multicellular forms known as magnetotactic multicellular prokaryotes (MMPs). 'Candidatus Magnetoglobus multicellularis' is presently the best known MMP. Here we describe the helical trajectories performed by these microorganisms as they swim forward, as well as their response to UV light. We measured the radius of the trajectory, time period and translational velocity (velocity along the helix axis), which enabled the calculation of other trajectory parameters such as pitch, tangential velocity (velocity along the helix path), angular frequency, and theta angle (the angle between the helix path and the helix axis). The data revealed that 'Ca. M. multicellularis' swims along elongated helical trajectories with diameters approaching the diameter of the microorganism. In addition, we observed that 'Ca. M. multicellularis' responds to UV laser pulses by swimming backwards, returning to forward swimming several seconds after the UV laser pulse. UV light from a fluorescence microscope showed a similar effect. Thus, phototaxis is used in addition to magnetotaxis in this microorganism.

Orientation response of haematophagous bugs to CO2: the effect of the temporal structure of the stimulus.

Carbon dioxide is generally recognized as an important cue used by haematophagous insects to locate a food source. When the mammalian hosts of these insects breathe, they normally emanate considerable amounts of CO2 at discrete intervals, i.e. with each exhalation. In this work, we analysed the effect of temporally pulsing CO2 on the host-seeking behaviour of Triatoma infestans. We investigated the ability of T. infestans to follow continuous and intermittent air pulses of 0.25, 0.5 and 1 Hz that included different concentrations of CO2. We found that insects were attracted to pulsed airstreams of 0.25 and 0.5 Hz transporting 400 ppm of CO2 above the ambient levels and to continuous streams added with the same amount of CO2. On the other hand, insects walked away from streams pulsed at rates of 1 Hz regardless of the amount of CO2 they bear. The walking trajectories displayed by bugs to attractive CO2-pulsed streams were as rectilinear and accurate as those to CO2-continuous streams. Our results are discussed in the frame of the interaction between olfactory and mechanoreceptive inputs as affecting the behavioural response of bugs.