MALTE DE VARIEDADES DE AMARANTO

Objetivou-se obter e avaliar o malte de amaranto, das espécies Amaranthus cruentus, com as variedades BRS Alegria e Verde, e Amaranthus caudatus, com a variedade Inca, produzidas no cerrado mato-grossense. Foi realizado teste de germinação com alternância no fotoperíodo. A qualidade do malte produzido foi avaliada pela análise do poder diastático e o rendimento. Observou-se, pela análise de fotoblastismo, que a variedade verde é fotoblástica neutra e BRS Alegria e Inca são pouco tolerantes à luz constante. O poder diastático, medido pelo índice WK variou em função da temperatura e variedades sendo que a variedade Inca teve maior rendimento e poder diastático (187,4 WK) à temperatura de 25 °C; a temperatura de 25 °C produziu maltes com maior poder diastático, da ordem de 168,4 WK; A variedade BRS Alegria teve menor poder diastático, sendo menos indicada para a produção de malte para fins cervejeiros. Os resultados foram satisfatórios para a produção de bebidas lácteas maltadas, no entanto, para fins cervejeiros, novos ensaios de maltagem devam ser conduzidos, na tentativa de elevar o poder diastático do malte deste pseudocereal para valores próximos do mínimo recomendado para este fim, que é de 220 WK. Palavras-chave: Amaranthus cruentus; Amaranthus caudatus; BRS Alegria; fotoblastismo; poder diastático. Amaranth varieties malt ABSTRACT: The objective of this study was to obtain and evaluate malt amaranth, of the species Amaranthus cruentus, with BRS Alegria and Verde varieties, and Amaranthus caudatus, with Inca variety. Germination test was performed with alternating photoperiod. The quality of the malt produced was evaluated by analyzing the diastatic power and the yield. It was observed, by the analysis of photoblastism, that the Verde variety is photoblastic neutral and BRS Alegria and Inca are poorly tolerant to constant light. Diastatic power, measured by the WK index, varied as a function of temperature and varieties, with the Inca variety having higher yields and diastatic power (187.4 WK) at a temperature of 25 °C; the temperature of 25 °C produced malts with greater diastatic power, in the order of 168.4 WK; The BRS-Alegria variety had lesser diastatic power, being less suitable for the production of malt for brewing purposes. The results were satisfactory for the production of malted dairy beverages, however, for brewing purposes, new malting tests should be conducted, in an attempt to raise the diastatic power of the malt of this pseudocereal to values ​​close to the minimum recommended for this purpose, which is 220 WK. Keywords: Amaranthus cruentus; Amaranthus caudatus; BRS Alegria; photoblastism; diastatic power.

Morphological and Chemical Evaluations of Leaf Surface on Particulate Matter2.5 (PM2.5) Removal in a Botanical Plant-Based Biofilter System

Particulate matter has been increasing worldwide causing air pollution and serious health hazards. Owing to increased time spent indoors and lifestyle changes, assessing indoor air quality has become crucial. This study investigated the effect of watering and drought and illumination conditions (constant light, light/dark cycle, and constant dark) on particulate matter2.5 (PM2.5) removal and surface characterization of leaf in a botanical plant-based biofilter system. Using Ardisia japonica and Hedera helix as experimental plants in the plant-based biofilter system, PM2.5, volatile organic carbon, and CO2, as the evaluators of indoor air quality, were estimated using a sensor. Morphological and chemical changes of the leaf surface (i.e., roughness and wax) associated with PM2.5 removal were characterized via scanning electron microscopy, Fourier transform infrared spectroscopy, and atomic force microscopy. The highest PM2.5 removal efficiency, stomata closure, high leaf roughness, and wax layer were observed under drought with constant light condition. Consequently, PM2.5 removal was attributed to the combined effect of leaf roughness and wax by adsorption rather than stomatal uptake. These results suggest that operating conditions of indoor plant-based biofilter system such as watering (or drought) and illumination may be applied as a potential strategy for enhancing PM2.5 removal.

Constant Light in Early Life Induces Depressive-Like Behavior in Chickens Via Modulation of Hippocampal BDNF/ERK Pathway

Background Light management plays an important role in broiler growth and behavior. Constant light in early post hatch stage has been a common practice for improving feed intake and body weight gain in broiler chickens, while whether and how constant light in early life affects the behavior in broiler chickens is rarely reported. Results In this study, newly hatched chickens were kept in either constant light (24L:0D, LL) or natural photoperiod (12L:12D, LD) for 7 days and maintained in constant light thereafter from 8 d to 21 d of age. Constant light did not affect chicken body weight, while increased average daily feed intake (ADFI) in 7 d and 21 d and every week feed conversion ratio (FCR). Constant light exposure in early life induces depressive-like behaviors, which was associated with higher corticosterone (CORT), lower melatonin and 5-hydroxytryptamine (5-HT) plasma. Concurrently, constant light exposure increased the mRNA expression of clock related genes and suppressed the expression of antioxidative genes in the hippocampus of both 7- and 21-day-old chickens. Moreover, brain derived neurotrophic factor (BDNF)/extracellular signal-regulated kinase (ERK) pathway in hippocampus was suppressed by constant light exposure. Conclusions These findings imply that constant light exposure in early life disrupts hippocampal expression of clock genes and BDNF/ERK pathway, which contributes to depressive-like behaviors in the chicken.

The effects of Levilactobacillus brevis on the physiological parameters and gut microbiota composition of rats subjected to desynchronosis

Background All living organisms have developed during evolution complex time-keeping biological clocks that allowed them to stay attuned to their environments. Circadian rhythms cycle on a near 24 h clock. These encompass a variety of changes in the body ranging from blood hormone levels to metabolism, to the gut microbiota composition and others. The gut microbiota, in return, influences the host stress response and the physiological changes associated with it, which makes it an important determinant of health. Lactobacilli are traditionally consumed for their prophylactic and therapeutic benefits against various diseases, namely, the inflammatory bowel syndrome, and even emerged recently as promising psychobiotics. However, the potential role of lactobacilli in the normalization of circadian rhythms has not been addressed. Results Two-month-old male rats were randomly divided into three groups and housed under three different light/dark cycles for three months: natural light, constant light and constant darkness. The strain Levilactobacillus brevis 47f was administered to rats at a dose of 0.5 ml per rat for one month and The rats were observed for the following two months. As a result, we identified the biomarkers associated with intake of L. brevis 47f. Changing the light regime for three months depleted the reserves of the main buffer in the cell—reduced glutathione. Intake of L. brevis 47f for 30 days restored cellular reserves of reduced glutathione and promoted redox balance. Our results indicate that the levels of urinary catecholamines correlated with light/dark cycles and were influenced by intake of L. brevis 47f. The gut microbiota of rats was also influenced by these factors. L. brevis 47f intake was associated with an increase in the relative abundance of Faecalibacterium and Roseburia and a decrease in the relative abundance of Prevotella and Bacteroides. Conclusions The results of this study show that oral administration of L. brevis 47f, for one month, to rats housed under abnormal lightning conditions (constant light or constant darkness) normalized their physiological parameters and promoted the gut microbiome's balance.

Ultraviolet screening by slug tissue and tight packing of plastids protect photosynthetic sea slugs from photoinhibition

One of the main mysteries regarding photosynthetic sea slugs is how the slug plastids handle photoinhibition, the constant light-induced damage to Photosystem II of photosynthesis. Recovery from photoinhibition involves proteins encoded by both the nuclear and plastid genomes, and slugs with plastids isolated from the algal nucleus are therefore expected to be incapable of constantly repairing the damage as the plastids inside the slugs grow old. We studied photoinhibition-related properties of the sea slug Elysia timida that ingests its plastids from the green alga Acetabularia acetabulum. Spectral analysis of both the slugs and the algae revealed that there are two ways the slugs use to avoid major photoinhibition of their plastids. Firstly, highly photoinhibitory UV radiation is screened by the slug tissue or mucus before it reaches the plastids. Secondly, the slugs pack the plastids tightly in their thick bodies, and therefore plastids in the outer layers protect the inner ones from photoinhibition. Both properties are expected to greatly improve the longevity of the plastids inside the slugs, as the plastids do not need to repair excessive amounts of damage.

Activity-dependent circuitry plasticity via the regulation of the histamine receptor level in the Drosophila visual system

Activity-dependent synaptic plasticity is crucial for responses to the environment. Although the plasticity mechanisms of presynaptic photoreceptor neurons in the Drosophila visual system have been well studied, postsynaptic modifications remain elusive. In addition, further studies on the adaption of the visual system to different light experiences at a circuitry scale are required. Using the modified transcriptional reporter of intracellular Ca2+ method, we describe a way to visualize circuitry changes according to different light experiences. We found enhanced postsynaptic neuronal activity responses in lamina monopolar neuron L2 after prolonged light treatment. Although L1 also has connections with photoreceptors, there were no enhanced activity responses in L1. We also report in this study that activity-dependent transcriptional downregulation of inhibitory histamine receptors (HRs) occurs in postsynaptic neuron L2, but not in L1, during continuous light conditions. We expressed exogenous HR proteins in L2 neurons and found that it attenuated the enhanced activity response caused by constant light exposure. These findings, together with the fact that histamine is the main inhibitory neurotransmitter released by photoreceptors in the Drosophila visual system, confirmed our hypothesis that the activity-dependent transcriptional downregulation of HRs is responsible for the constant light exposure-induced circuitry response changes in L2. The results successfully demonstrated the selective circuit change after synaptic remodeling evoked by long-term activation and provided in vivo evidence of circuitry plasticity upon long-term environmental stimulation.

A quantitative model of sporadic axonal degeneration in the Drosophila visual system

In human neurodegenerative diseases, neurons undergo axonal degeneration months to years before they die. Here, we developed a system modelling early degenerative events in Drosophila adult photoreceptor cells. Thanks to the stereotypy of their axonal projections, this system delivers quantitative data on sporadic and progressive axonal degeneration of photoreceptor cells. Using this method, we show that exposure of adult flies to a constant light stimulation for several days overcomes the intrinsic resilience of R7 photoreceptors and leads to progressive axonal degeneration. This was not associated with apoptosis. We furthermore provide evidence that loss of synaptic integrity between R7 and a postsynaptic partner preceded axonal degeneration, thus recapitulating features of human neurodegenerative diseases. Finally, our experiments uncovered that neurotransmission to postsynaptic partners of R7 and their response are required to initiate degeneration, suggesting that postsynaptic cells signal back to the photoreceptor to maintain axonal structure. This model can be used to dissect cellular circuit mechanisms involved in the early events of axonal degeneration, allowing for a better understanding of how neurons cope with stress and lose their resilience capacities.

Arabidopsis thaliana PRR7 Provides Circadian Input to the CCA1 Promoter in Shoots but not Roots

The core of the plant circadian clock involves multiple interlocking gene expression loops and post-translational controls along with inputs from light and metabolism. The complexity of the interactions is such that few specific functions can be ascribed to single components. In previous work, we reported differences in the operation of the clocks in Arabidopsis shoots and roots, including the effects of mutations of key clock components. Here, we have used luciferase imaging to study prr7 mutants expressing CCA1::LUC and GI::LUC markers. In mature shoots expressing CCA1::LUC, loss of PRR7 radically altered behaviour in light:dark cycles and caused loss of rhythmicity in constant light but had little effect on roots. In contrast, in mature plants expressing GI::LUC, loss of PRR7 had little effect in light:dark cycles but in constant light increased the circadian period in shoots and reduced it in roots. We conclude that most or all of the circadian input to the CCA1 promoter in shoots is mediated by PRR7 and that loss of PRR7 has organ-specific effects. The results emphasise the differences in operation of the shoot and root clocks, and the importance of studying clock mutants in both light:dark cycles and constant light.

The opposing Chloride Cotransporters KCC and NKCC control locomotor activity in constant light and during long days

Cation Chloride Cotransporters (CCC’s) regulate intracellular chloride ion concentration ([Cl−]i) within neurons, which can reverse the direction of the neuronal response to the neurotransmitter GABA. Na+ K+ Cl− (NKCC) and K+ Cl− (KCC) cotransporters transport Cl− into or out of the cell, respectively. When NKCC activity dominates, the resulting high [Cl−]i can lead to an excitatory and depolarizing response of the neuron upon GABAA receptor opening, while KCC dominance has the opposite effect. This inhibitory-to-excitatory GABA switch has been linked to seasonal adaption of circadian clock function to changing day length, and its dysregulation is associated with neurodevelopmental disorders such as epilepsy. Constant light normally disrupts circadian clock function and leads to arrhythmic behavior. Here, we demonstrate a function for KCC in regulating Drosophila locomotor activity and GABA responses in circadian clock neurons because alteration of KCC expression in circadian clock neurons elicits rhythmic behavior in constant light. We observed the same effects after downregulation of the Wnk and Fray kinases, which modulate CCC activity in a [Cl−]i-dependent manner. Patch-clamp recordings from clock neurons show that downregulation of KCC results in a more positive GABA reversal potential, while KCC overexpression has the opposite effect. Finally, KCC downregulation represses morning behavioral activity during long photoperiods, while downregulation of NKCC promotes morning activity. In summary, our results support a model in which the regulation of [Cl−]i by a KCC/NKCC/Wnk/Fray feedback loop determines the response of clock neurons to GABA, which is important for adjusting behavioral activity to constant light and long-day conditions.