Protein storage vacuoles (PSV) are the main repository of protein in dicotyledonous seeds, but little is known about the origins of these transient organelles. PSV are hypothesized to either arise de ...novo or originate from the preexisting embryonic vacuole (EV) during seed maturation. Here, we tested these hypotheses by studying PSV formation in Arabidopsis (Arabidopsis thaliana) embryos at different stages of seed maturation and recapitulated this process in Arabidopsis leaves reprogrammed to an embryogenic fate by inducing expression of the LEAFY COTYLEDON2 transcription factor. Confocal and immunoelectron microscopy indicated that both storage proteins and tonoplast proteins typical of PSV were delivered to the preexisting EV in embryos or to the lytic vacuole in reprogrammed leaf cells. In addition, sectioning through embryos at several developmental stages using serial block face scanning electron microscopy revealed the 3D architecture of forming PSV. Our results indicate that the preexisting EV is reprogrammed to become a PSV in Arabidopsis.
Zn2+ plays an important role in the normal function of the endoplasmic reticulum (ER) and its deficiency can cause ER stress, which is related to a wide range of diseases. In order to provide tools ...to better understand the role of mobile Zn2+ in ER processes, the first custom designed ER-localised fluorescent Zn2+ probes have been developed through the introduction of a cyclohexyl sulfonylurea as an ER-targeting unit with different Zn2+ receptors. Experiments in vitro and in cellulo show that both probes have a good fluorescence switch on response to Zn2+, high selectivity over other cations, low toxicity, ER-specific targeting ability and are efficacious imaging agents for mobile Zn2+ in four different cell lines. Probe 9 has been used to detect mobile Zn2+ changes under ER stress induced by both tunicamycin or thapsigargin, which indicates that the new probes should allow a better understanding of the mechanisms cells use to respond to dysfunction of zinc homeostasis in the ER and its role in the initiation and progression of diseases to be developed.
The endoplasmic reticulum (ER) is a highly dynamic polygonal membrane network composed of interconnected tubules and sheets (cisternae) that forms the first compartment in the secretory pathway ...involved in protein translocation, folding, glycosylation, quality control, lipid synthesis, calcium signalling, and metabolon formation. Despite its central role in this plethora of biosynthetic, metabolic and physiological processes, there is little quantitative information on ER structure, morphology or dynamics. Here we describe a software package (AnalyzER) to automatically extract ER tubules and cisternae from multi-dimensional fluorescence images of plant ER. The structure, topology, protein-localisation patterns, and dynamics are automatically quantified using spatial, intensity and graph-theoretic metrics. We validate the method against manually-traced ground-truth networks, and calibrate the sub-resolution width estimates against ER profiles identified in serial block-face SEM images. We apply the approach to quantify the effects on ER morphology of drug treatments, abiotic stress and over-expression of ER tubule-shaping and cisternal-modifying proteins.
Zn
2+
plays an important role in the normal function of the endoplasmic reticulum (ER) and its deficiency can cause ER stress, which is related to a wide range of diseases. In order to provide tools ...to better understand the role of mobile Zn
2+
in ER processes, the first custom designed ER-localised fluorescent Zn
2+
probes have been developed through the introduction of a cyclohexyl sulfonylurea as an ER-targeting unit with different Zn
2+
receptors. Experiments
in vitro
and
in cellulo
show that both probes have a good fluorescence switch on response to Zn
2+
, high selectivity over other cations, low toxicity, ER-specific targeting ability and are efficacious imaging agents for mobile Zn
2+
in four different cell lines. Probe
9
has been used to detect mobile Zn
2+
changes under ER stress induced by both tunicamycin or thapsigargin, which indicates that the new probes should allow a better understanding of the mechanisms cells use to respond to dysfunction of zinc homeostasis in the ER and its role in the initiation and progression of diseases to be developed.
Two endoplasmic reticulum (ER) targeting probes were developed to image mobile Zn
2+
to help understand Zn
2+
related biological processes in the ER.
The endoplasmic reticulum forms the first compart- ment in a series of organelles which comprise the secretory pathway, it takes the form of an extremely dynamic and pleomorphic membrane-bounded ...network of tubules and cisternae which have numerous different cellular functions. In this review, we discuss the nature of endoplasmic reticulum structure and dynamics, its relationship with closely associated organelles, and its possible function as a highway for the distribution and delivery of a diverse range of structures from metabolic complexes to viral particles.
meta-Phenylene bis(phenylurea) receptors 1–4 were designed and synthesized to investigate the association between receptor shape, anion-selective binding and anion-directed self-assembly processes. ...Solution studies, performed through 1H NMR titrations with a variety of tetra-N-butylammonium salts, demonstrated strong binding of 2 equiv of H2PO4 –, AcO–, BzO– anions and comparatively weak binding of Cl–, HSO4 –, and SO4 2– anions. Binding modes and stability constants (log β) were determined by regression analysis of the obtained 1H NMR titration data in DMSO-d 6, and the cooperativities of the binding interactions were probed. Host–guest complexes of receptors 1 and 2 were studied in the crystalline phase to further probe the anion-binding behavior of this motif. This included a triple-stranded helicate consisting of three strands of receptor 2 arranged around a mixed-phosphate anionic core, which was characterized by using X-ray crystallography.
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