Earthworms show a wide spectrum of regenerative potential with certain species like Eisenia fetida capable of regenerating more than two-thirds of their body while other closely related species, such as Paranais litoralis seem to have lost this ability. Earthworms belong to the phylum Annelida, in which the genomes of the marine oligochaete Capitella telata and the freshwater leech Helobdella robusta have been sequenced and studied. Herein, we report the transcriptomic changes in Eisenia fetida (Indian isolate) during regeneration. Following injury, E. fetida regenerates the posterior segments in a time spanning several weeks. We analyzed gene expression changes both in the newly regenerating cells and in the adjacent tissue, at early (15days post amputation), intermediate (20days post amputation) and late (30 days post amputation) by RNAseq based de novo assembly and comparison of transcriptomes. We also generated a draft genome sequence of this terrestrial red worm using short reads and mate-pair reads. An in-depth analysis of the miRNome of the worm showed that many miRNA gene families have undergone extensive duplications. Sox4, a master regulator of TGF-beta mediated epithelial-mesenchymal transition was induced in the newly regenerated tissue. Genes for several proteins such as sialidases and neurotrophins were identified amongst the differentially expressed transcripts. The regeneration of the ventral nerve cord was also accompanied by the induction of nerve growth factor and neurofilament genes. We identified 315 novel differentially expressed transcripts in the transcriptome, that have no homolog in any other species. Surprisingly, 82% of these novel differentially expressed transcripts showed poor potential for coding proteins, suggesting that novel ncRNAs may play a critical role in regeneration of earthworm.

This paper presents an adaptive fuzzy logic based controller for the depth control of an Autonomous Underwater Vehicle(AUV). The kinematic and dynamic motion of an AUV is described using six degree of freedom differential equations of motion using bodyand earth-fixed frame of references. Due to hydrodynamic forces, these equations are complex, non-linear and highly coupled therefore are impractical for use in controller design. In practice, system is commonly decomposed into three noninteractive systems such as diving subsystem, steering subsystem and speed subsystem. In this study a reduced order model was derived for diving system using depth plane dynamics and a suitable dual loop control strategy is formulated by synthesizing fuzzy logic based control in series with a phase lead dynamic compensator to achieve the desired set point tracking and reasonably good performance objectives under variety of disturbances encountered in oceanic environments.The obvious benefits of this type of approach lies in the simplicity of the scheme compared to the conventional deterministic systems and easy implementation for real time control of the Autonomous Underwater Vehicles. The proposed fuzzy logic based controller accepts deterministic information, the depth of the vehicle as input and achieves imprecise reasoning and de-fuzzification to generate a deterministic control output which manipulates the pitch angle and hence the depth of the vehicle. The simulated results clearly demonstrate the efficacy of this approach as compared to the conventional PID controller designed and tuned using Ziegler-Nichols scheme.

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Eisenia fetida, the common vermicomposting earthworm, shows robust regeneration of posterior segments removed by amputation. During the period of regeneration, the newly formed tissue initially contains only undifferentiated cells but subsequently differentiates into a variety of cell types including muscle, nerve and vasculature. Transcriptomics analysis, reported previously, provided a number of candidate non-coding RNAs that were induced during regeneration. We found that one such long non-coding RNA (lncRNA) is expressed in the skin, only at the base of newly formed chaetae. The spatial organization and precise arrangement of the regenerating chaetae and the cells expressing the lncRNA on the ventral side clearly support a model wherein the regenerating tissue contains a zone of growth and cell division at the tip and a zone of differentiation at the site of amputation. The temporal expression pattern of the lncRNA, christened Neev, closely resembled the pattern of chitin synthase genes, implicated in chaetae formation. We found that the lncRNA harbours 49 sites for binding a set of four miRNAs while the Chitin Synthase 8 mRNA comprises 478 sites. The over-representation of shared miRNA sites suggests that lncRNA Neev may act as a miRNA sponge to transiently de-repress chitin synthase 8 during formation of new chaetae in the regenerating segments of Eisenia fetida.