Identification of a Major Lipid Droplet Protein in a Marine Diatom Phaeodactylum tricornutum

Various kinds of organisms, including microalgae, accumulate neutral lipids in distinct intracellular compartments called lipid droplets. Generally, lipid droplets are generated from the endoplasmic reticulum, and particular proteins localize on their surface. Some of these proteins function as structural proteins to prevent fusion between the lipid droplets, and the others could have an enzymatic role or might be involved in intracellular membrane trafficking. However, information about lipid droplet proteins in microalgae is scarce as compared with that in animals and land plants. We focused on the oil-producing, marine, pennate diatom Phaeodactylum tricornutum that forms lipid droplets during nitrogen deprivation and we investigated the proteins located on the lipid droplets. After 6 d of cultivation in a nitrate-deficient medium, the mature lipid droplets were isolated by sucrose density gradient centrifugation. Proteomic analyses revealed five proteins, with Stramenopile-type lipid droplet protein (StLDP) being the most abundant protein in the lipid droplet fraction. Although the primary sequence of StLDP did not have homology to any known lipid droplet proteins, StLDP had a central hydrophobic domain. This structural feature is also detected in oleosin of land plants and in lipid droplet surface protein (LDSP) of Nannochloropsis species. As a proline knot motif of oleosin, conservative proline residues existed in the hydrophobic domain. StLDP was up-regulated during nitrate deprivation, and fluctuations of StLDP expression levels corresponded to the size of the lipid droplets

Complete Genomic Structure of the Bloom-forming Toxic Cyanobacterium Microcystis aeruginosa NIES-843

The nucleotide sequence of the complete genome of a cyanobacterium, Microcystis aeruginosa NIES-843, was determined. The genome of M. aeruginosa is a single, circular chromosome of 5 842 795 base pairs (bp) in length, with an average GC content of 42.3%. The chromosome comprises 6312 putative protein-encoding genes, two sets of rRNA genes, 42 tRNA genes representing 41 tRNA species, and genes for tmRNA, the B subunit of RNase P, SRP RNA, and 6Sa RNA. Forty-five percent of the putative protein-encoding sequences showed sequence similarity to genes of known function, 32% were similar to hypothetical genes, and the remaining 23% had no apparent similarity to reported genes. A total of 688 kb of the genome, equivalent to 11.8% of the entire genome, were composed of both insertion sequences and miniature inverted-repeat transposable elements. This is indicative of a plasticity of the M. aeruginosa genome, through a mechanism that involves homologous recombination mediated by repetitive DNA elements. In addition to known gene clusters related to the synthesis of microcystin and cyanopeptolin, novel gene clusters that may be involved in the synthesis and modification of toxic small polypeptides were identified. Compared with other cyanobacteria, a relatively small number of genes for two component systems and a large number of genes for restriction-modification systems were notable characteristics of the M. aeruginosa genome

Effects of Quizzes in Marking Supported E-Learning

Marking on a textbook when studying is a natural and subjective learning activity conducted by a learner. Such activity can be positively utilized in the learning process. If we could extract marked phrases or sentences, it will be possible to develop personalized quizzes to support active learning. In this study, we presented a learning support model to use quizzes generated from markings on a digital teaching document. In this paper, the framework of the environment is explained. We conducted three experimental studies to explore the effects of the quizzes in the learning process. We examined the changes of marking after these quizzes, as well as the test scores corresponding to the markings. We conclude that the proposed model can be useful in improving e-learning

Building an experimental system to examine a method for supporting verbal explanation

© 2016 IEEE. In the future digital textbooks, a new media is desired to support verbal explanation of subjective knowledge. In this study, we used the scenario of conveying pottery skill as an example to explore a practical method for passing subjective knowledge. We proposed a method and built a prototype system to support verbal explanation of the feeling or sense of force, which is essential in explaining pottery skills. In the system, a force feedback device was integrated. Preliminary experimental results indicate that the method is feasible and can be integrated with a digital textbook

A Study on Haptic Media to Support Verbal Explanations

A digital textbook is an educational tool and possible to convey knowledge through a variety of teaching and learning media such as texts, graphs, figures, audios, and videos attached as digital data embedded in the contents. We might feel like we can understand other people’s experiential knowledge through their verbal explanations or expository text with those additional supportive media. However, it is uncertain what we obtained is actually the same as what to be conveyed, because this knowledge is subjective and appears different in the human sensors or receptors. For example, if we obtained knowledge through haptic perception then it will be difficult to explain because of its implicit and subjective characteristics. Even if visual or audio media are used to support the explanation, it is still insufficient and the receivers usually cannot understand it objectively. A new medium such as using a haptic device along with an expository text might help in this case. However, up to now there is no digital textbook equipped with such supporting media. Toward the future of digital textbooks, a new medium to pass on subjective knowledge such as feeling of touch or sense of force will be desired. Therefore firstly, it is necessary to investigate the possibility of a new medium to convey such an intuitive knowledge. In this paper, we present our studies of knowledge acquisition using an experimental system which helps acquire verbal explanation along with haptic or sense of force knowledge. Taking an example of conveying a potter’s knowledge, specifically skills in forming clay cup with a trowel, our preliminary results showed that it is promising to use haptic support for verbal explanations in some situations

Preliminary Study of Haptic Media for Future Digital Textbooks

A digital textbook is capable to convey knowledge through a variety of learning media. Nowadays a digital textbook is still mainly consisted of verbal explanations which are traditionally called expository text. The conveying of knowledge in the format of expository text can be supported by various media such as graphs, figures, audios, and videos embedded in a digital textbook. These conventional learning media focus on auditory and visual human senses. Therefore, they are insufficient to support the learning of subjective bodily information regarding feeling of touch and sense of force. In this case, adoption of haptic media can potentially fill in the gap. Up to now there is no digital textbook system which is equipped with such supporting media. In a foreseeable future, a digital textbook system can be attached with haptic devices to pass on subjective information such as feeling of touch through human senses other than auditory and visual senses. To make that a reality, it is necessary to explore the potentials of these media to convey subjective bodily information. In this paper, we first present a generic model explaining bodily knowledge acquisition and display with the new media for a future digital textbook system. We then present a preliminary case study exploring possibilities of using a haptic device to convey a potter’s knowledge, specifically the potter’s skills in forming clay cups with a trowel. We introduce our initial experiments and discuss future work in using haptic media to support learning of expository text