Functional conversion of fatty acyl-CoA synthetase to firefly luciferase by site-directed mutagenesis: A key substitution responsible for luminescence activity

AbstractWe demonstrated that firefly luciferase has a catalytic function of fatty acyl-CoA synthesis [Oba, Y., Ojika, M. and Inouye, S. (2003) Firefly luciferase is a bifunctional enzyme: ATP-dependent monooxygenase and a long chain fatty acyl-CoA synthetase. FEBS Lett. 540, 251–254] and proposed that the evolutionary origin of beetle luciferase is a fatty acyl-CoA synthetase (FACS) in insect. In this study, we performed the functional conversion of FACS to luciferase by replacing a single amino acid to serine. This serine residue is conserved in luciferases and possibly interacts with luciferin. The mutants of FACSs in non-luminous click beetle Agrypnus binodulus (AbLL) and Drosophila melanogaster (CG6178) gave luminescence enhancement, suggesting that the serine residue is a key substitution responsible for luminescence activity

Bioluminescent Fishes and their Eyes

What shaped the evolution of vision in fish more than anything else is the need to see, be it to avoid obstacles or find shelters, and recognize conspecifics, predators and prey. However, for vision to be effective, sufficient light has to be available. While there is no shortage of light in shallow water depths, at least during the day, the situation for species occurring at greater depths is a different one: they live in an environment where sunlight does not reach, but which nevertheless, is not totally devoid of light. Numerous marine organisms, including fishes of at least 46 families, possess the ability to ‘bioluminesce’, i.e. they can produce biological light. This chapter focuses on the interaction between bioluminescence and specific photoreceptor adaptations in fishes to detect the biological light

Semi-Intrinsic Luminescence in Marine Organisms

Light emission is widespread in the oceans, with over three quarters of all observed marine species exhibiting bioluminescence. Several organisms such as the copepod Metridia pacifica and the ostracod Vargula hilgendorfii have been proven to synthesise their luciferin and luciferase to facilitate light emission. However, many luminescent species lack the capability to do this and instead it is possible that they acquire some of the components for their luminescence through predation or filter feeding on organisms that produce luciferins or precursors to these molecules. This has resulted in many organisms using certain luciferins, such as coelenterazine, as their substrate without possessing a clear mechanism to synthesise these. This chapter will review several examples of these semi-intrinsic luminescent systems and how the substrates and enzymes can be obtained for these reactions. Moreover, it will look at why particular luciferins, such as coelenterazine, are more widespread and utilised in this manner compared to other substrates

Indigenous utilization of termite mounds and their sustainability in a rice growing village of the central plain of Laos

<p>Abstract</p> <p>Background</p> <p>The objective of this study was to investigate the indigenous utilization of termite mounds and termites in a rain-fed rice growing village in the central plain of Laos, where rice production is low and varies year-to-year, and to assess the possibility of sustainable termite mound utilization in the future. This research was carried out from 2007 to 2009.</p> <p>Methods</p> <p>The termites were collected from their mounds and surrounding areas and identified. Twenty villagers were interviewed on their use of termites and their mounds in the village. Sixty-three mounds were measured to determine their dimensions in early March, early July and middle to late November, 2009.</p> <p>Results</p> <p>Eleven species of Termitidae were recorded during the survey period. It was found that the villagers use termite mounds as fertilizer for growing rice, vegetable beds and charcoal kilns. The villagers collected termites for food and as feed for breeding fish. Over the survey period, 81% of the mounds surveyed increased in volume; however, the volume was estimated to decrease by 0.114 m³mound^-1year^-1on average due to several mounds being completely cut out.</p> <p>Conclusion</p> <p>It was concluded that current mound utilization by villagers is not sustainable. To ensure sustainable termite utilization in the future, studies should be conducted to enhance factors that promote mound restoration by termites. Furthermore, it will be necessary to improve mound conservation methods used by the villagers after changes in the soil mass of mounds in paddy fields and forests has been measured accurately. The socio-economic factors that affect mound utilization should also be studied.</p

The role of infection in the development of non-valvular atrial fibrillation: Up-regulation of Toll-like receptor 2 expression levels on monocytes

SummaryMany studies have suggested that inflammation may participate in the pathogenesis of non-valvular atrial fibrillation (AF). However, it has been unknown by exposure to what the inflammation is caused. Recently, we reported that Toll-like receptor 2 (TLR2) level on monocytes was significantly up-regulated in viral and bacterial infections, but not in non-infectious inflammatory states. Our purpose was to test the hypothesis that expression of TLR2 levels may be up-regulated in patients with non-valvular AF. A total of 48 consecutive patients with non-valvular AF who were hospitalized for catheter ablation were enrolled in this study. TLR2 levels were assayed by using flow-cytometric analysis and compared with volunteers in sinus rhythm (control group, n=24). Additionally, C-reactive protein (CRP) and interleukin-6 (IL-6) levels were assayed, and the left atrial volume indexes (LAVI) in the non-valvular AF group were measured. The results demonstrated that TLR2 levels in the non-valvular AF group were significantly higher than in the control group (median, 4682 vs. 3866 sites/cell; P<0.01). Moreover, non-valvular AF patients had significantly higher IL-6 levels than controls. However, there was no significant difference in CRP levels between the two groups. It was observed in 44 AF patients, in whom pulmonary vein isolation was confirmed to be successful, that the LAVI significantly diminished 1 month after ablation (median, 33.6 vs. 29.5ml/m2; P<0.001), but not the TLR2 and IL-6 levels. Our results implied that an infectious inflammation may participate in the pathogenesis of non-valvular AF

Decreased activity in the reward network of chronic insomnia patients

In modern society, many people have insomnia. Chronic insomnia has been noted as a risk factor for depression. However, there are few functional imaging studies of the brain on affective functions in chronic insomnia. This study aimed to investigate brain activities induced by emotional stimuli in chronic insomnia patients. Fifteen patients with primary insomnia and 30 age and gender matched healthy controls participated in this study. Both groups were presented images of fearful, happy, and neutral expressions consciously and non-consciously while undergoing MRI to compare the activity in regions of the brain responsible for emotions. Conscious presentation of the Happy-Neutral contrast showed significantly lower activation in the right orbitofrontal cortex of patients compared to healthy controls. The Happy-Neutral contrast presented in a non-conscious manner resulted in significantly lower activation of the ventral striatum, right insula, putamen, orbitofrontal cortex and ventral tegmental area in patients compared to healthy controls. Our findings revealed that responsiveness to positive emotional stimuli were decreased in insomniac patients. Specifically, brain networks associated with rewards and processing positive emotions showed decreased responsiveness to happy emotions especially for non-conscious image. The magnitude of activity in these areas also correlated with severity of insomnia, even after controlling for depression scale scores. These findings suggest that insomnia induces an affective functional disorder through an underlying mechanism of decreased sensitivity in the regions of the brain responsible for emotions and rewards to positive emotional stimuli

The Luminous Fungi of Japan

Luminous fungi have long attracted public attention in Japan, from old folklore and fiction to current tourism, children’s toys, games, and picture books. At present, 25 species of luminous fungi have been discovered in Japan, which correspond to approximately one-fourth of the globally recognized species. This species richness is arguably due to the abundant presence of mycophiles looking to find new mushroom species and a tradition of night-time activities, such as firefly watching, in Japan. Bioluminescence, a field of bioscience focused on luminous organisms, has long been studied by many Japanese researchers, including the biochemistry and chemistry of luminous fungi. A Japanese Nobel Prize winner, Osamu Shimomura (1928–2018), primarily focused on the bioluminescence system of luminous fungi in the latter part of his life, and total elucidation of the mechanism was finally accomplished by an international research team with representatives from Russia, Brazil, and Japan in 2018. In this review, we focused on multiple aspects related to luminous fungi of Japan, including myth, taxonomy, and modern sciences

Firefly luciferase is a bifunctional enzyme: ATP-dependent monooxygenase and a long chain fatty acyl-CoA synthetase

AbstractFirefly luciferase can catalyze the formation of fatty acyl-CoA via fatty acyl-adenylate from fatty acid in the presence of ATP, Mg2+ and coenzyme A (CoA). A long chain fatty acyl-CoA (C16–C20), produced by luciferase from a North American firefly (Photinus pyralis) and a Japanese firefly (Luciola cruciata), was isolated and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis. Of a number of substrates tested, linolenic acid (C18:3) and arachidonic acid (C20:4) appear to be suitable for acyl-CoA synthesis. This evidence suggests that firefly luciferase within peroxisomes of the cells in the photogenic organ may be a bifunctional enzyme, catalyzing not only the bioluminescence reaction but also the fatty acyl-CoA synthetic reaction