HMAS: enabling seamless collaboration between drones, quadruped robots, and human operators with efficient spatial awareness

Heterogeneous robots equipped with multi-modal sensors (e.g., UAV, wheeled and legged terrestrial robots) provide rich and complementary functions that may help human operators to accomplish complex tasks in unknown environments. However, seamlessly integrating heterogeneous agents and making them interact and collaborate still arise challenging issues. In this paper, we define a ROS 2 based software architecture that allows to build incarnated heterogeneous multi-agent systems (HMAS) in a generic way. We showcase its effectiveness through a scenario integrating aerial drones, quadruped robots, and human operators (see https://youtu.be/iOtCCticGuk). In addition, agent spatial awareness in unknown outdoor environments is a critical step for realizing autonomous individual movements, interactions, and collaborations. Through intensive experimental measurements, RTK-GPS is shown to be a suitable solution for achieving the required locating accuracy

Amoebae for clustering: a bio-inspired cellular automata method for data classification

We present a bio-inspired mechanism for data clustering. Our method uses amoebae which evolve according to cellular automata rules: they contain the data to be processed and emit reaction-diffusion waves at random times. The waves transmit the information across the lattice and causes other amoebae to react, by being attracted or repulsed. The local reactions produce small homogeneous groups which progressively merge and realise the clustering at a larger scale. Despite the simplicity of the local rules, interesting complex behaviour occur, which make the model robust to various changes of its settings. We evaluate this prototype with a simple task: the separation of two groups of integer values distributed according to Gaussian laws

Targeting of proConA to the Plant Vacuole depends on its Nine Amino-acid C-terminal Propeptide

Concanavalin A (ConA) is a well characterized and extensively used lectin accumulated in the protein bodies of jack bean cotyledons. ConA is synthesized as an inactive precursor proConA. The maturation of inactive proConA into biologically active ConA is a complex process including the removal of an internal glycopeptide and a C-terminal propeptide (CTPP), followed by a head-to-tail ligation of the two largest polypeptides. The cDNA encoding proConA was cloned and expressed in tobacco BY-2 cells. ProConA was slowly transported to the vacuole where its maturation into ConA was similar to that in jack bean cotyledons, apart from an incomplete final ligation. To investigate the role of the nine amino acid CTPP, a truncated form lacking the propeptide (proConAΔ9) was expressed in BY-2 cells. In contrast to proConA, proConAΔ9 was rapidly chased out of the endoplasmic reticulum (ER) and secreted into the culture medium. The CTPP was then fused to the C-terminal end of a secreted form of green fluorescent protein (secGFP). When expressed in tobacco BY-2 cells and leaf protoplasts, the chimaeric protein was located in the vacuole whereas secGFP was located in the culture medium and in the vacuole. Altogether, our results show we have isolated a new C-terminal vacuolar sorting determinan

Arginine/Lysine Residues in the Cytoplasmic Tail Promote ER Export of Plant Glycosylation Enzymes

Plant N-glycan processing enzymes are arranged along the early secretory pathway, forming an assembly line to facilitate the step-by-step modification of oligosaccharides on glycoproteins. Thus, these enzymes provide excellent tools to study signals and mechanisms, promoting their localization and retention in the endoplasmic reticulum (ER) and Golgi apparatus. Herein, we focused on a detailed investigation of amino acid sequence motifs present in their short cytoplasmic tails in respect to ER export. Using site-directed mutagenesis, we determined that single arginine/lysine residues within the cytoplasmic tail are sufficient to promote rapid Golgi targeting of Golgi-resident N-acetylglucosaminyltransferase I (GnTI) and α-mannosidase II (GMII). Furthermore, we reveal that an intact ER export motif is essential for proper in vivofunction of GnTI. Coexpression studies with Sar1p provided evidence for COPII-dependent transport of GnTI to the Golgi. Our data provide evidence that efficient ER export of Golgi-resident plant N-glycan processing enzymes occurs through a selective mechanism based on recognition of single basic amino acids present in their cytoplasmic tails

Ricin B chain targeted to the endoplasmic reticulum of tobacco protoplasts is degraded by a CDC48- and vacuole-independent mechanism

The B chain of ricin was expressed and delivered to the endoplasmic reticulum of tobacco protoplasts where it disappeared with time in a manner consistent with degradation. This turnover did not occur in the vacuoles or upon secretion. Indeed, several lines of evidence indicate that, in contrast to the turnover of endoplasmic reticulum-targeted ricin A chain in the cytosol, the bulk of expressed ricin B chain was degraded in the secretory pathway

Inhibition of Golgi function causes plastid starch accumulation

Little is known about possible interactions between chloroplasts and the Golgi apparatus, although there is increasing evidence for a direct Golgi to chloroplast transport pathway targeting proteins to their destinations within the membranes and stroma of plastids. Here data are presented showing that a blockage of secretion results in a significant increase of starch within plastids. Golgi disassembly promoted either by the secretory inhibitor brefeldin A or through an inducible Sar1-GTP system leads to dramatic starch accumulation in plastids, thus providing evidence for a direct interaction between plastids and Golgi activity. The possibility that starch accumulation is due either to elevated levels of cytosolic sugars because of loss of secretory Golgi activity or even to a blockage of amylase transport from the Golgi to the chloroplast is discussed

Function of the anion transporter AtCLC-d in the trans-Golgi network

Anion transporting proteins of the CLC type are involved in anion homeostasis in a variety of organisms. CLCs from Arabidopsis have been shown to participate in nitrate accumulation and storage. In this study, the physiological role of the functional chloride transporter AtCLC-d from Arabidopsis was investigated. AtCLC-d is weakly expressed in various tissues, including the root. When transiently expressed as a GFP fusion in protoplasts, it co-localized with the VHA-a1 subunit of the proton-transporting V-type ATPase in the trans-Golgi network (TGN). Stable expression in plants showed that it co-localized with the endocytic tracer dye FM4-64 in a brefeldin A-sensitive compartment. Immunogold electron microscopy confirmed the localization of AtCLC-d to the TGN. Disruption of the AtCLC-d gene by a T-DNA insertion did not affect the nitrate and chloride contents. The overall morphology of these clcd-1 plants was similar to that of the wild-type, but root growth on synthetic medium was impaired. Moreover, the sensitivity of hypocotyl elongation to treatment with concanamycin A, a blocker of the V-ATPase, was stronger in the clcd-1 mutant. These phenotypes could be complemented by overexpression of AtCLC-d in the mutant background. The results suggest that the luminal pH in the trans-Golgi network is adjusted by AtCLC-d-mediated transport of a counter anion such as Cl− or NO3−

The morphogenesis of the zebrafish eye, including a fate map of the optic vesicle

We have examined the morphogenesis of the zebrafish eye, from the flat optic vesicle at 16 hours post fertilization (hpf) to the functional hemispheric eye at 72 hpf. We have produced three-dimensional reconstructions from semithin sections, measured volumes and areas, and produced a fate map by labeling clusters of cells at 14–15 hpf and finding them in the 24 hpf eye cup. Both volume and area increased sevenfold, with different schedules. Initially (16–33 hpf), area increased but volume remained constant; later (33–72 hpf) both increased. When the volume remained constant, the presumptive pigmented epithelium (PE) shrank and the presumptive neural retina (NR) enlarged. The fate map revealed that during 14–24 hpf cells changed layers, moving from the PE into the NR, probably through involution around the margin of the eye. The transformation of the flat epithelial layers of the vesicle into their cup-shaped counterparts in the eye was also accompanied by cellular rearrangements; most cells in a cluster labeled in the vesicle remained neighbors in the eye cup, but occasionally they were separated widely. This description of normal zebrafish eye development provides explanations for some mutant phenotypes and for the effects of altered retinoic acid. Dev Dyn;218:175–188. © 2000 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/35166/1/15_ftp.pd

Differential effects of human and plant N-acetylglucosaminyltransferase I (GnTI) in plants

In plants and animals, the first step in complex type N-glycan formation on glycoproteins is catalyzed by N-acetylglucosaminyltransferase I (GnTI). We show that the cgl1-1 mutant of Arabidopsis, which lacks GnTI activity, is fully complemented by YFP-labeled plant AtGnTI, but only partially complemented by YFP-labeled human HuGnTI and that this is due to post-transcriptional events. In contrast to AtGnTI-YFP, only low levels of HuGnTI-YFP protein was detected in transgenic plants. In protoplast co-transfection experiments all GnTI-YFP fusion proteins co-localized with a Golgi marker protein, but only limited co-localization of AtGnTI and HuGnTI in the same plant protoplast. The partial alternative targeting of HuGnTI in plant protoplasts was alleviated by exchanging the membrane-anchor domain with that of AtGnTI, but in stably transformed cgl1-1 plants this chimeric GnTI still did not lead to full complementation of the cgl1-1 phenotype. Combined, the results indicate that activity of HuGnTI in plants is limited by a combination of reduced protein stability, alternative protein targeting and possibly to some extend to lower enzymatic performance of the catalytic domain in the plant biochemical environment

NtGNL1 Plays an Essential Role in Pollen Tube Tip Growth and Orientation Likely via Regulation of Post-Golgi Trafficking

Background: Tobacco GNOM LIKE 1 (NtGNL1), a new member of the Big/GBF family, is characterized by a sec 7 domain. Thus, we proposed that NtGNL1 may function in regulating pollen tube growth for vesicle trafficking. Methodology/Principal Findings: To test this hypothesis, we used an RNAi technique to down-regulate NtGNL1 expression and found that pollen tube growth and orientation were clearly inhibited. Cytological observations revealed that both timing and behavior of endocytosis was disrupted, and endosome trafficking to prevacuolar compartments (PVC) or multivesicular bodies (MVB) was altered in pollen tube tips. Moreover, NtGNL1 seemed to partially overlap with Golgi bodies, but clearly colocalized with putative late endosome compartments. We also observed that in such pollen tubes, the Golgi apparatus disassembled and fused with the endoplasmic reticulum, indicating abnormal post-Golgi trafficking. During this process, actin organization was also remodeled. Conclusions/Significance: Thus, we revealed that NtGNL1 is essential for pollen tube growth and orientation and it likel